Method of manufacturing three-dimensional object, liquid set for manufacturing three-dimensional object, device for manufacturing three-dimensional object, and gel object

ABSTRACT

A method of manufacturing a three-dimensional object includes imparting a first liquid having a first composition including a solvent and a curable material and a second liquid having a second composition to form a liquid film, curing the liquid film, and repeating the imparting and the curing to obtain the three-dimensional object, wherein the imparting position and the imparting amount of each of the first liquid and the second liquid are controlled in such a manner that the liquid film includes multiple areas where at least one of post-curing compression stress and post-curing modulus of elasticity is different.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of and claims the benefit ofpriority to U.S. application Ser. No. 15/194,934, filed Jun. 28, 2016,which is based on and claims priority pursuant to 35 U.S.C. § 119 toJapanese Patent Application Nos. 2015-135174, 2015-145139, 2015-145151,2015-231140, and 2016-063311, filed on Jul. 6, 2015, Jul. 22, 2015, Jul.22, 2015, Nov. 26, 2015, and Mar. 28, 2016, respectively, in the JapanPatent Office, the entire disclosures of which are hereby incorporatedby reference herein.

BACKGROUND Technical Field

The present invention relates to a method of manufacturing athree-dimensional object, a liquid set for manufacturing athree-dimensional object, a device for manufacturing a three-dimensionalobject, and a gel object.

Description of the Related Art

3D printing or Additive Manufacturing (AM) is known as a technology toform a three-dimensional object.

This technology calculates cross-sections sliced vertical to laminationdirection and forms and laminates respective layers according to theform of cross-sections to form a three-dimensional object.

As the method of manufacturing a three-dimensional object, for example,a fused deposition molding (FDM) method, an inkjetting method, a binderjetting method, a material jetting method, a stereo lithographyapparatus (SLA) method, and a selective laser sintering method areknown. Of these, images of photocurable liquid resins are formed atpositions for a three-dimensional object by the material jetting methodand multi-layered to form the three-dimensional object.

A device for manufacturing the three-dimensional object is developed,which laminates forming materials according to the filling ratio or themixing ratio indicating the degree of density of the forming materialsand changes the mass by using different materials depending on areas orparts to form a three-dimensional object.

SUMMARY

According to the present invention, provided is an improved method ofmanufacturing a three-dimensional object which includes imparting afirst liquid having a first composition including a solvent and acurable material and a second liquid having a second composition to forma liquid film, curing the liquid film, and repeating the imparting andthe curing to obtain the three-dimensional object, wherein the impartingposition and the imparting amount of each of the first liquid and thesecond liquid are controlled in such a manner that the liquid filmincludes multiple areas where at least one of post-curing compressionstress and post-curing modulus of elasticity is different.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Various other objects, features and attendant advantages of the presentinvention will be more fully appreciated as the same becomes betterunderstood from the detailed description when considered in connectionwith the accompanying drawings in which like reference charactersdesignate like corresponding parts throughout and wherein:

FIG. 1 is a schematic diagram illustrating an example of strengthdistribution in a three-dimensional object (hydrogel object) of Example1 described later containing water as the main ingredient when changingthe mass ratio of the first liquid and the second liquid in the hydrogelobject per layer;

FIG. 2 is a diagram illustrating a view of the hydrogel objectillustrated in FIG. 1 when the hydrogel object stands on its side;

FIG. 3 is a schematic diagram illustrating an example of the mass ratiodistribution of the first liquid and the second liquid in the hydrogelobject (three-dimensional object) of Example 2 described latercontaining water as the main ingredient;

FIG. 4 is a schematic diagram illustrating the modulus of elasticitydistribution under 20 percent compression in FIG. 3;

FIG. 5 is a schematic diagram illustrating an example of the mass ratiodistribution of the first liquid and the second liquid in the hydrogelobject (three-dimensional object) of Example 3 described latercontaining water as the main ingredient;

FIG. 6 is a schematic diagram illustrating the modulus of elasticitydistribution under 20 percent compression in FIG. 5;

FIG. 7 is a schematic diagram illustrating an example of the mass ratiodistribution of the first liquid and the second liquid in the hydrogelobject (three-dimensional object) of Example 4 described latercontaining water as the main ingredient;

FIG. 8 is a schematic diagram illustrating the modulus of elasticitydistribution under 20 percent compression in FIG. 7;

FIG. 9 is a graph illustrating an example of the change of modulus ofelasticity and compression stress when the mass ratio of the firstliquid and the second liquid in the hydrogel object (three-dimensionalobject) of Example 5 described later containing water as the mainingredient is changed;

FIG. 10 is a graph illustrating an example of the change of modulus ofelasticity and compression stress when the mass ratio of the firstliquid and the second liquid in the hydrogel object (three-dimensionalobject) of Example 6 described later containing water as the mainingredient is changed;

FIG. 11 is a graph illustrating an example of the change of modulus ofelasticity and compression stress when the mass ratio of the firstliquid and the second liquid in the hydrogel object (three-dimensionalobject) of Example 7 described later containing water as the mainingredient is changed;

FIG. 12 is a schematic diagram illustrating an example of the mass ratiodistribution of the first liquid and the second liquid in the hydrogelobject (three-dimensional object) of Example 8 described latercontaining water as the main ingredient;

FIG. 13 is a schematic diagram illustrating the modulus of elasticitydistribution under 20 percent compression in FIG. 12;

FIG. 14 is a schematic diagram illustrating an example of the mass ratiodistribution of the first liquid and the second liquid in the oil object(three-dimensional object) of Example 9;

FIG. 15 is a schematic diagram illustrating the modulus of elasticitydistribution at 20 percent compression in FIG. 14;

FIG. 16 is a schematic diagram illustrating an example of the mass ratiodistribution of the first liquid and the second liquid in the oil gelobject (three-dimensional object) of Example 10;

FIG. 17 is a schematic diagram illustrating the modulus of elasticitydistribution at 20 percent compression in FIG. 16;

FIG. 18 is a schematic diagram illustrating an example of the mass ratiodistribution of the first liquid and the second liquid in the hydrogelobject (three-dimensional object) of Comparative Example 1 describedlater including water as the main ingredient;

FIG. 19 is a schematic diagram illustrating the modulus of elasticitydistribution under 20 percent compression in FIG. 18;

FIG. 20 is a schematic diagram illustrating an example of the device formanufacturing a three-dimensional object for use in the method ofmanufacturing a three-dimensional object according to an embodiment ofthe present invention;

FIG. 21 is a schematic diagram illustrating an example in which thefirst liquid and the second liquid according to the liquid dischargingmethod according to an embodiment of the present disclosure;

FIG. 22 is a schematic diagram illustrating an example where the massratio distribution of the first liquid and the second liquid are changedin the three-dimensional object according to an embodiment of thepresent invention;

FIG. 23 is a schematic diagram illustrating an example of the device formanufacturing a three-dimensional object for use in the method ofmanufacturing a three-dimensional object according to an embodiment ofthe present invention;

FIG. 24 is a schematic diagram illustrating an example of the device formanufacturing a three-dimensional object for use in the method ofmanufacturing a three-dimensional object according to an embodiment ofthe present invention;

FIG. 25 is a schematic diagram illustrating an example of the device formanufacturing a three-dimensional object for use in the method ofmanufacturing a three-dimensional object according to an embodiment ofthe present invention;

FIG. 26 is a diagram illustrating a method of obtaining a dimensionaccuracy of a three-dimensional object;

FIG. 27 is a diagram illustrating a state in which the three-dimensionalobject is supported by a support structure; and

FIG. 28 is a diagram illustrating a state in which the three-dimensionalobject is separated from the support structure.

The accompanying drawings are intended to depict example embodiments ofthe present invention and should not be interpreted to limit the scopethereof. The accompanying drawings are not to be considered as drawn toscale unless explicitly noted.

DESCRIPTION OF THE EMBODIMENTS

Method of Manufacturing Three-dimensional Object and Device forManufacturing Three-dimensional Object

The method of manufacturing a three-dimensional object of the presentdisclosure includes discharging liquid including a first liquidincluding a solvent and a curable material and a second liquid having adifferent composition (second composition) from the first composition ofthe first liquid to form a liquid film, curing the liquid film to form acured layer, and repeating the discharging and the curing to manufacturethe three-dimensional object, wherein the imparting position and theimparting amount of each of the first liquid and the second liquid arecontrolled in such a manner that the liquid film includes multiple areaswhere at least one of post-curing compression stress and post-curingmodulus of elasticity is different.

The method of manufacturing a three-dimensional object of the presentdisclosure is based on what the present inventors have found, which isthat forming a liquid film having multiple areas where at least one ofpost-curing compression stress and post-curing modulus of elasticity ora device which simply forms such a liquid film has not been developedyet.

The present inventors have found the following:

Gels have mixed characteristics of liquid and a solid and include asolvent stably taken inside the three-dimensional network of organicpolymer compounds, etc. These are widely used in the fields of medicine,medical care, food, agriculture, and industry. Of these gels, gelshaving water as the main ingredient of the solvent (also hereinafterreferred to as hydrogel) have biological compatibility due to highcontaining ratio of water so that application thereof to medical care isexpected.

In addition, needs for three-dimensional objects formed of a gel or ahydrogel having a soft form which can control hardness in thethree-dimensional object are increasing on application to alternatives(for example, cartilage and hyaline body of eye balls, etc.) of abiological body.

However, no method of manufacturing a three-dimensional objectreproducing a complex and fine structure from three-dimensional data orfreely controlling hardness inside the three-dimensional object is notprovided yet in reality.

To manufacture a three-dimensional object, it is preferable to usetypical inkjet three-dimensional object manufacturing methods. However,the present inventors have found that it is extremely difficult tocontrol hardness of the inside of an obtained three-dimensional object.

The method of manufacturing a three-dimensional object of the presentdisclosure includes a first process of imparting a first liquid having afirst composition including a solvent and a curable material and asecond liquid having a second composition to form a liquid film and asecond process of curing the liquid film, and repeating the firstprocess and the second process multiple times to obtain thethree-dimensional object, wherein the imparting position and theimparting amount of each of the first liquid and the second liquid arecontrolled in such a manner that the liquid film includes multiple areaswhere at least one of post-curing compression stress and post-curingmodulus of elasticity are different. There is no specific limitation tohow many times the imparting (first process) and the curing (secondprocess) are repeated. It can be suitably selected to suit to the sizeand form of a three-dimensional object to be manufactured.

With regard to the size of the three-dimensional object, the averagethickness per layer is preferably 10-50 μm. When the average thicknessis 10-50 μm, it is possible to accurately manufacture athree-dimensional object free of peel-off so that the layers are piledup as high as the three-dimensional object.

In the method of manufacturing a three-dimensional object, the positionand the amount of the first liquid and the second liquid to be impartedare controlled so that a liquid film is formed which has multiple areaswhere at least one of post-curing compression stress and post-curingmodulus of elasticity is continuously different. Therefore, it ispossible to efficiently manufacture a three-dimensional object includingareas each having different compression stress and modulus ofelasticity.

The multiple areas where at least one of post-curing compression stressand post-curing modulus of elasticity is continuously different arepresent in the same liquid film or across films obtained in the firstprocess. Of these, it is preferable that the post-curing compressionstress and/or post-curing modulus of elasticity be continuouslydifferent in the same film obtained in the first process.

With regard to the position and the amount of the first liquid and thesecond liquid, there is no specific limitation thereto and they can besuitably selected to suit to a particular application if they aredifferent in a single film or across films.

In addition, it is also preferable that the method of manufacturing athree-dimensional object include an embodiment including a liquidimparting process to impart the first liquid and the second liquid inthe liquid set for manufacturing a three-dimensional object describedlater and a film curing process to cure the imparted film.

Each process in the method of manufacturing a three-dimensional objectis described in detail.

First Process and First Device

The first process (liquid imparting process) includes imparting thefirst liquid containing a solvent and a curable material and the secondliquid having different composition from that of the first liquid to asingle area.

The first process is suitably conducted by a liquid imparting device toimpart the first liquid and the second liquid.

There is no specific limitation to the method of imparting the firstliquid and the second liquid as long as liquid droplets are applied to atarget area with an appropriate precision. The method can be suitablyselected to suit to a particular application. For example, a liquiddischarging method is suitable. For example, the liquid dischargingmethod includes a dispenser method, a spray method, or an inkjet method.Known devices are used to conduct these methods.

Of these, the dispenser method is excellent liquid quantitative propertybut the application area is small. The spray method is capable of simplyforming a fine discharging material, has a wide application area, anddemonstrates excellent applicability but the quantitative propertythereof is poor so that powder scatters due to the spray stream. Theinkjet method has a good quantitative property in comparison with thespray method and a wider application area in comparison with thedispenser method. Accordingly, the inkjet method is capable ofaccurately and efficiently forming a complex object. For this reason, inthe present disclosure, using the inkjet method is preferable.

When the liquid discharging method is used, it is preferable to have anozzle capable of discharging the first liquid and the second liquid. Asfor the nozzle, nozzles in a known inkjet printer can be suitably used.In addition, it is possible to use, for example, MH5420/5440(manufactured by Ricoh Industry Company, Ltd.). It is preferable to usethe inkjet printer because the head portion can drip a large amount ofthe liquid at once and the application area is large, which leads tohigh application performance.

First Liquid

The first liquid includes a solvent, a curable material, and otheroptional ingredients.

The first liquid has a different composition from the second liquid.

Solvent

Specific examples of the solvent include, but are not limited to, water,alcohol, ketone, ether, ester, and hydrocarbons. These can be used aloneor in combination.

Specific examples of alcohol include, but are not limited to, methanol,ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutyl alcohol,tert-butyl alcohol, 1-pentanol, 1-hexanol, 1-octanol, 2-ethyl-1-hexanol,allyl alcohol, benzyl alcohol, cyclohexanol, 1,2-ethane diol,1,2-propane diol, 2-methoxy ethanol, 2-ethoxy ethanol, 2-propoxyethanol, 2-(methoxyethoxy)ethanol, 1-methoxy-2-propanol, dipropyleneglycol monomethylether, diacetone alcohol, ethyl carbitol, and butylcarbitol. These can be used alone or in combination.

Specific examples of the ketone include, but are not limited to,acetone, methyl ethyl ketone, 2-pentanone, 3-pentanonoe, 2-hexanone,methyl isobutyl ketone, 2-heptanone, 4-heptanone, diisobutylketone, andcyclohexanone. These can be used alone or in combination.

Specific examples of the ether include, but are not limited to,diethylether, dipropylether, diisopropylether, dibutylether,1,4-dioxane, tetrahydrofuran, and 1,2-diethoxyethane. These can be usedalone or in combination.

Specific examples of the ester include, but are not limited to, methylacetate, ethyl formate, propyl formate, ethyl formate, propyl acetate,butyl acetate, ethylene glycol monoethylether acetate, ethylene glycolmonobutylether acetate, hydroxyethylmethacrylate, hydroxyethyl acrylate,γ-butylolactone, methyl methacrylate, isobutyl acrylate, cyclohexylacrylate, 2-ethoxyethyl acrylate, trifluoroethyl acrylate, and glycidylmethacrylate. These can be used alone or in combination.

Specific examples of the hydrocarbon include, but are not limited to,n-hexane, cyclohexane, benzene, toluene, xylene, solvent naphtha,styrene, and halogen hydrocarbon such as dichloromethane andtrichloroethylene. These can be used alone or in combination.

Of these, water and toluene are preferable.

Curable Materials

There is no specific limitation to the curable material and a suitablecurable material is selected to suit to a particular application. Forexample, compounds having a photopolymerizable functional group ispreferable and polymerizable monomers are more preferable.

There is no specific limitation to the polymerizable monomer. It can beselected to suit to a particular application. Compounds including anethylenic unsaturated group curable by a photopolymerization initiatorproducing a radical such as a (meth)acryloyl group, a vinyl group, andan allyl group and compounds having a cyclic ether group curable by aphotoacid generator producing an acid such as an epoxy group arepreferable. In terms of curing property, compounds including anethylenic unsaturated group are more preferable.

Examples of the compound including an ethylenic unsaturated group arecompounds having (meth)acrylamide group, (meth)acrylate compounds,compounds having a (meth)acryloyl group, compounds having a vinyl group,and compounds having an allyl group.

As the polymerizable monomer, for example, monovalent polymerizablemonomers and polyfuncitonal polymerizable monomers are suitable. Thesecan be used alone or in combination.

Monovalent Polymerizable Monomer

Specific examples of the monovalent polymerizable monomer include, butare not limited to, acrylamide, N-substituted acrylamide derivatives,N,N-di-substituted acrylamide derivatives, N-substituted methacrylamidederivatives, N—N-di-substituted methacrylamide derivatives,2-ethylhexyl(meth)acrylate (EHA), 2-hydroxyethyl(meth)acrylate (HEA),2-hydroxypropyl(meth)acrylate (HPA), caprolactone-modifiedtetrahydrofurfuryl(meta)acrylate, isobonyl(meth)acrylate,3-methoxybutyl(meth)acrylate, tetrahydro furfuryl(meth)acrylate,lauryl(meth)acrylate, 2-phenoxyethyl (meth)acrylate,isodecyl(meth)acrylate, isooctyl(meth)acrylate, tridecyl(meth)acrylate,caprolactone(meth)acrylate, and ethoxyfied nonylphenol(meth)acrylate.

These can be used alone or in combination. Of these, acrylamide,N,N-dimethylacrylamide, N-isopropylacrylamide, and acryloyl morpholineare preferable.

Organic polymers can be obtained by polymerizing the mono-valentpolymerizable monomer.

The proportion of the mono-valent polymerizable monomer is 0.5-20percent by mass to the total amount of the first liquid.

Polyfunctional Polymerizable Monomer

Furthermore, the polyfuncitonal polymerizable monomer includes abi-functional polymerizable monomer and a tri- or higher functionalpolymerizable monomer. These can be used alone or in combination.

Specific examples of the bi-functional monomer include, but are notlimited to, tripropylene glycol di(meth)acrylate, tri ethylene glycoldi(meth)acrylate, tetraethyl ene glycol di(meth)acrylate, polypropyleneglycol di(meth)acrylate, neopentyl glycol hydroxy pivalic acid esterdi(meth)acrylate (MANDA), hydroxypivalic acid neopentyl glycol esterdi(meth)acrylate (HPNDA), 1,3-butanediol di(meth)acrylate (BGDA),1,4-butanediol di(meth)acrylate (BUDA), 1,6-hexanediol di(meth)acrylate(HDDA), 1,9-nonane diol(meth)acrylate, diethylene glycoldi(meth)acrylate (DEGDA), neopentyl glycol di(meth)acrylate (NPGDA),tripropylene glycol di(meth)acrylate (TPGDA), caprolactone-modifiedhydroxy pivalic acid neopentyl glycol ester di(meth)acrylate,propoxinated neopentyl glycol di(meth)acrylate, ethoxy-modifiedbisphenol A di(meth)acrylate, polyethylene glycol 200 di(meth)acrylate,polyethylene glycol 400 di(meth)acrylate, and methylenebis acrylamide.These can be used alone or in combination.

Specific examples of the tri- or higher functional polymerizablemonomers include, but are not limited to, trimethylol propanetri(meth)acrylate (TMPTA), pentaerythritol tri(meth)acrylate (PETA),dipentaerythritol hexa(meth)acrylate (DPHA), tirallyl isocyanate,ε-caprolactone modified dipentaerythritol (meth)acrylate,tris(2-hydroxyethyl)isocyanulate, ethoxified trimethylol propanetri(meth)acrylate, propoxified trimethylol propane tri(meth)acrylate,propoxified glyceryl tri(meth)acrylate, pentaerythritoltetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate,pentaerythritol tetra(meth)acrylate, dipentaerythritolhydroxypenta(meth)acrylate, ditrimethylol propane tetra(meth)acrylate,ethoxified(pentaerythritol) tetra(meth)acrylate, and penta(meth)acrylateester.

These can be used alone or in combination.

The proportion of the polyfunctional polymerizable monomer is 0.01-10mol percent to the total amount of the mono-functional monomer in thefirst liquid. When the proportion is 0.01-10 mol percent, gelcompression stress is easily adjusted.

When the three-dimensional object is an internal organ model, thethree-dimensional object is preferably a soft three-dimensional objectof a hydrogel object containing water as the main ingredient.

As the soft three-dimensional object, an organic-inorganic hydrogel ispreferable which contains water and an ingredient dissoluble in thewater in a three-dimensional network structure formed by complexing awater-soluble organic polymer and a dispersion of a laminate claymineral.

In this case, the first liquid preferably includes water and hygrogelprecursor. The first liquid containing water and the hygrogel precursoris also referred to as “material for soft shape forming object”.

Water

As the water, deionized water, ultrafiltered water, reverse osmosiswater, pure water such as distilled water, and ultra pure water aresuitable.

It is suitable to dissolve or disperse other ingredients such as organicsolvents in the water to impart moisturizing property, antibioticproperty, and conductivity and adjust compression stress and modulus ofelasticity.

Property of Hydrogel Precursor

The hygrogel precursor contains a mineral, a polymerizable monomer, andoptional other ingredients.

Mineral

The mineral has no specific limitation and is suitably selected to suitto a particular application. For example, minerals dispersible in waterare suitable.

An example of the mineral dispersible in water is a dispersion of alaminated clay mineral.

The dispersion of the laminated clay mineral is uniformly dispersible inwater at the level of primary crystal.

Specific examples thereof include, but are not limited to, waterswellable smectite and water swellable mica. More specific examplesinclude, but are not limited to, water swellable hectorite containingsodium as ion between layers, water swellable montmorillonite, waterswellable saponite, and water swellable synthesized mica. These can beused alone or in combination. Also, these can be appropriatelysynthesized or available on the market.

Specific examples of the product available on the market include, butare not limited to, synthesized hectorite (laponite XLG, manufactured byRockWood), SWN (manufactured by Coop Chemical Ltd.), and fluorinatedhectorite SWF (manufactured Coop Chemical Ltd.).

There is no specific limitation to the proportion of the mineral and itcan be suitably selected to suit to a particular application. It ispreferably 1-40 part by mass to the total content of the first liquid.

Polymerizable Monomer

As the polymerizable monomer in the hydrogel precursor, it is possibleto use the same polymerizable monomer as the curable material in thefirst liquid.

The polymerizable monomer is polymerized to become an organic polymer.

As the organic polymer, water soluble organic polymers are preferable interms of usage of hydrogel precursor.

As the water-soluble organic polymer, water-soluble organic polymershaving, for example, an amide group, an amino group, a hydroxyl group, atetramethyl ammonium group, a silanol group, an epoxy group, etc. aresuitable.

The water soluble organic polymers having an amide group, an aminogroup, a hydroxyl group, a tetramethyl ammonium group, a silanol group,an epoxy group, etc. are advantageous to maintain the strength of ahydrogel.

The volume of the droplet of the first liquid has no particularlimitation and can be suitably selected to suit to a particularapplication. For example, the volume is preferably 2-60 pL and morepreferably 15-30 pL. When the volume of the droplet of the first liquidis 2 pL or greater, the discharging stability is improved. When thevolume is 60 pL or less, filling a discharging nozzle for forming(shape-forming) with liquid is easy.

There is no specific limitation to the amount (percent by mass) of thefirst liquid in the liquid film formed in the first process. It can beselected to suit to a particular application. The amount is controlledbased on the imparting amount of the first liquid.

The imparting amount of the first liquid is calculated by multiplyingthe volume of the liquid droplet of the first liquid by the number ofdroplets in the first liquid.

Other Ingredients

The other optional ingredients in the first liquid have no particularlimit. For example, stabilizers, surface treatment chemicals,polymerization initiators, coloring materials, viscosity modifiers,drying retarders, adhesion imparting agents, antioxidants, anti-agingagents, cross-linking promoters, ultraviolet absorbents, plasticizers,preservatives, dispersants, and polymerization promoters.

Stabilizer

Stabilizers are used to disperse and stabilize the mineral to keep a solstate.

In addition, stabilizers are also optionally used to stabilizeproperties of the liquid in the liquid discharging method.

As the stabilizer, for example, highly concentrated phosphates, glycols,and non-union surfactants are suitable.

The non-union surfactants can be synthesized or products available onthe market are also usable. A specific example of the product is LS106(Kao Corporation).

Surface Treatment Chemical

Specific examples of the surface treatment chemical include, but are notlimited to, polyester resins, polyvinyl acetate resins, silicone resins,coumarone resins, esters of aliphatic acids, glyceride, and wax.

Polymerization Initiator

Examples of the polymerization initiator are thermal polymerizationinitiators and photopolymerization initiators. Of these, in terms ofstorage stability, photopolymerization initiators are preferable becauseit produces a radical or a cation at irradiation of an active energyray.

As the photopolymerization initiator, any material can be used whichproduces a radical at irradiation of light (ultraviolet having in awavelength range of 220-400 nm).

Specific examples of the photopolymerization initiator include, but arenot limited to, acetophenone, 2,2-di ethoxyacetophenone,p-dimethylaminoacetone, benzophenone, 2-chlorobenzophenone,p,p′-dichlorobenzophenone, p,p-bi sdiethylamonobenzophenoen, Michler'sKetone, benzyl, benzoin, benzoin methylether, benzoin ethylether,benzoin isopropylether, benzoin-n-propylether, benzoin isobutylether,benzoin-n-butylether, benzyl methyl ketal, thioxanthone,2-chlorothioxanthone, 2-hydroxy-2-methyl-1-phenyl-1-one,1-(4-isopropylphenyl)-2-hydroxy-2-methylpropane-1-one, methylbenzoylformate, 1-hydroxy cyclohexyl phenylketone, azobisisobutylo nitrile,benzoylperoxide, and di-tert-butylperoxide. These can be used alone orin combination.

The photopolymerization initiator is available on the market. A specificexample thereof is Irgacure 184 (manufactured by BASF).

The thermal polymerization initiator has no particular limitation andcan be suitably selected to suit to a particular application. Examplesthereof are azo-based initiators, peroxides initiators, persulfateinitiators, and oxidation-reduction initiators. These can be used aloneor in combination.

Specific example of the azo-based initiator include, but are not limitedto, VA-044, VA-46B, VA-50, VA-057, VA-061, VA-067, VA-086,2,2′-azobis(4-methoxy-2,4-dimethylvaleronitrile)(VAZO 33),2,2′-azobis(2-amidinopropane)dihydrochloride (VAZO 50),2,2′-azobis(2,4-dimetaylvaleronitrile) (VAZO 52),2,2′-azobis(isobutylonitrile) (VAZO 64),2,2′-azobis-2-methylbutylonitrile) (VAZO 67), and1,1-azobis(1-cyclohexane carbonitrile) (VAZO 88) (all available fromDupont Chemical), 2,2′-azobis(2-cyclopropylpropionitrile), and2,2′-azo-bis(methylisobutylate) (V-601) (all available from Wako PureChemical Industries, Ltd.). These can be used alone or in combination.

Specific examples of the peroxide initiator include, but are not limitedto, benzoyl peroxide, acetyl peroxide, lauroyl peroxide, decanoylperoxide, dicetyl peroxy dicarbonate, di(4-t-butylcyclohexyl)peroxydicarbonate (Perkadox 16S) (available from Akzo Nobel),di(2-ethylhexyl)peroxy dicarbonate, t-butyl peroxypivalate (Lupersol 11)(all available from Elf Atochem), t-butylperoxy-2-ethyl hexanoate(Trigonox 21-050) (available from Akzo Nobel), and dicumyl peroxide.These can be used alone or in combination.

Specific examples of the persulfate initiator include, but are notlimited to, potassium persulfate, sodium persulfate, ammoniumpersulfate, and sodium peroxodisulfate. These can be used alone or incombination.

Specific examples of oxidation-reduction initiator include, but are notlimited to, a combination of the persulfate initiator and a reducingagent such as methacid sodium sulfite and acid sodium sulfite, a systembased on the organic peroxide and tertiary amine (such as a system basedon benzoyl peroxide and dimethylaniline), and a system based on organichydroperoxide and transition metal (such as a system based oncumenhydroperoxide and cobalt naftate). These can be used alone or incombination.

The photopolymerization initiator is preferably independently includedin the second liquid having a composition different from that of thefirst liquid. When the photopolymerization initiator is not included inthe first liquid but in the second liquid only, storage stability of thefirst liquid is improved. Also, in terms of storage storage stability,additives can be added more than the case in which the polymerizationinitiator is used in the first liquid. Therefore, the polymerizationratio of a three-dimensional object increases, thereby improvingefficiency of manufacturing.

Like the case of the photopolymerization initiator, the thermalpolymerization initiator is preferably included in the second liquid interms of storage stability of the first liquid. It is preferable tocontain a polymerization promoter.

In addition, the proportion of the photopolymerization initiator ispreferably not greater than 1 percent by mass to the total content ofthe liquid set for a three-dimensional object. When the proportion isnot greater than 1 percent by mass, inhibition of curing reaction can beprevented after the first liquid and the second liquid are mixed.

Coloring Agent

The coloring agent may be included in the first liquid and/or the secondliquid. However, it is preferable that the second liquid contain thecoloring agent.

The coloring agent are dissolved or stably dispersed in the secondliquid. As the coloring agent, dyes and pigments having excellentthermal stability are suitable. Of these, solvent dyes are preferable.Two or more kinds of coloring agents can be mixed to adjust colors.

For example, black dyes, magenta dyes, cyan dyes, and yellow dyes aresuitable as the dye.

Specific examples of the black dyes include, but are not limited to, MSBLACK VPC (manufactured by Mitsui Chemicals, Incorporated), AIZEN SOTBLACK-1 and AIZEN SOT BLACK-5 (Both manufactured by HODOGAYA CHEMICALCO., LTD.), RESORIN BLACK GSN 200% and RESOLIN BLACK BS (bothmanufactured by Bayer Holding Ltd.), KAYASET BLACK A-N (manufactured byNippon Kayaku Co., Ltd., DAIWA BLACK MSC (manufactured by Daiwa FineChemicals Co., Ltd.), HSB-202 (manufactured by Mitsubishi ChemicalCorporation), NEPTUNE BLACK X60 and NEOPEN BLACK X58 (Manufactured byBASF), Oleosol Fast BLACK RL (manufactured by Taoka Chemical Co., Ltd.,Chuo BLACK80 and Chuo BLACK80-15 (manufactured by Chuo syntheticChemical Co., Ltd.).

Specific examples of the magenta dye include, but are not limited to, MSMagenta VP, MS Magenta HM-1450, and MS Magenta Hso-147 (All manufacturedby Mitsui Chemicals, Incorporated), AIZEN SOT Red-1, AIZEN SOT Red-2,AIZEN SOT Red-3, AIZEN SOT Pink-1, SPIRON Red GEHSPECIAL (allmanufactured by HODOGAYA CHEMICAL CO., LTD.), RESOLIN Red FB 200%,MACROLEX Red Violet R, MACROLEX ROT 5B (all manufactured by BayerHolding Ltd.), KAYASET ReD B, KAYASET Red 130, and KAYASET ReD 802(Manufactured by Nippon Kayaku Co., Ltd.), PHLOXIN, ROSE BENGAL, andACID Red (all manufactured by Daiwa Fine Chemicals Co., Ltd.), HSR-31AND DIARESIN RedK (both manufactured by Mitsubishi ChemicalCorporation), Oil Red (manufactured by BASF), and Oil Pink330(manufactured by Chuo synthetic Chemical Co., Ltd.).

Specific examples of the cyan dye include, but are not limited to, MSCyan HM-1238, MS Cyan HSo-16, Cyan Hso-144, and MS Cyan VPG (allmanufactured by Mitsui Chemicals, Incorporated), AIZEN SOT Blue-4(manufactured by HODOGAYA CHEMICAL CO., LTD.), RESOLIN BR.BLUE BGLN200%, MACROLEX Blue RR, CERES Blue GN, SIRUS SUPRATURQ.Blue Z-BGL, andSIRUS SUPRA TURQ.Blue FB-LL330% (all manufactured by Bayer HoldingLtd.), KAYASET Blue Fr, KAYASET Blue N. KAYASET Blue 814, Turq.Blue GL-5200, and LightBlue BGL-5 200 (all manufactured by Nippon Kayaku Co.,Ltd.), DAIWA Blue 7000 and Oleosol Fast Blue GL (both manufactured byDaiwa Fine Chemicals Co., Ltd.), DIARESINBLUE P (manufactured byMitsubishi Chemical Corporation), SUDAN Blue 670, NEOPEN Blue808, andZAPON Blue 806 (all manufactured by BASF).

Specific examples of the yellow dye include, but are not limited to, MSYellow HSm-41, Yellow KX-7, and Yellow EX-27 (manufactured by MitsuiChemicals, Incorporated), AIZEN SOT Yellow-1, AIZEN SOT Yellow-3, andAIZEN SOT Yellow-6 (all manufactured by HODOGAYA CHEMICAL CO., LTD.),MACROLEX Yellow 6G, MACROLEX FLUOR, and Yellow 10GN (all manufactured byBayer Holding Ltd.), KAYASET Yellow SF-G, KAYASET Yellow 2G, KAYASETYellow A-G, and KAYASET Yellow E-G (all manufactured by Nippon KayakuCo., Ltd.), DAIWA Yellow 330HB (Daiwa Fine Chemicals Co., Ltd.), HSY-68(Mitsubishi Chemical Corporation), SUDAN Yellow 146 and NEOPEN Yellow075 (all manufactured by BASF), and Oil Yellow 129 (manufactured by Chuosynthetic Chemical Co., Ltd.)

Examples of the pigments include organic pigments and inorganicpigments. For example, azo pigments (azo lake, insoluble azo pigments,condensed azo pigments, chelate azo pigments, etc.), polycyclic pigments(phthalocyanine pigments, perylene pigments, anthraquinone pigments,quinacridone pigments, di oxazine pigments, thioindigo pigments,isoindolinone pigments, and quinofuranone pigments).

Specific examples of the pigment include, but are not limited to, theorganic pigments and inorganic pigments referenced by the followingnumber in Color Index.

Red or Magenta Pigments:

Pigment Red 3, 5, 19, 22, 31, 38, 43, 48:1, 48:2, 48:3, 48:4, 48:5,49:1, 53:1, 57:1, 57:2, 58:4, 63:1, 81, 81:1, 81:2, 81:3, 81:4, 88, 104,108, 112, 122, 123, 144, 146, 149, 166, 168, 169, 170, 177, 178, 179,184, 185, 208, 216, 226, 257, Pigment Violet 3, 19, 23, 30, 37, 50, 88,and Pigment Orange 13, 16, 20, and 36.

Blue or cyan pigments:

Pigment Blue 1, 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, 17-1, 22, 27, 28,29, 36, and 60

Green pigments:

Pigment Green 7, 26, 36, and 50.

Yellow pigments:

Pigment Yellow 1, 3, 12, 13, 14, 17, 34, 35, 37, 55, 74, 81, 83, 93, 94,95, 97, 108, 109, 110, 137, 138, 139, 153, 154, 155, 157, 166, 167, 168,180, 185, and 193.

Black pigments:

For example, Pigment Black 7, 26, and 28 are suitable.

The pigments are available on the market. Specific examples thereofinclude, but are not limited to, CHROMOFINE YELLOW 2080, 5900, 5930,AF-1300, 2700L, CHROMOFINE ORANGE 3700L, 6730, CHROMOFINE SCARLET 6750,CHROMOFINE MAGENTA 6880, 6886, 6891N, 6790, and 6887, CHROMOFINE VIOLETRE, CHROMOFINE RED 6820, 6830, CHROMOFINE BLUE HS-3, 5187, 5108, 5197,5085N, SR-5020, 5026, 5050, 4920, 4827, 4837, 4824, 4933GN-EP, 4940,4973, 5205, 5208, 5214, 5221, 5000P, CHROMOFINE GREEN 2GN, 2G0, 2G-500D,5310, 5370, 6830, CHROMOFINE BLACK A-1103, SEIKAFAST Yellow, 10GH, A-3,2035, 2054, 2200, 2270, 2300, 2400(B), 2500, 2600, ZAY-260, 2700(B), and2770, SEIKAFAST RED 8040, C405(F), CA120, LR-116, 1531B, 8060R, 1547,ZAW-262, 1537B, GY, 4R-4016, 3820, 3891, ZA-215, SEIKAFAST CARMINE6B1476T-7, 1483LT, 6840, and 3870, SEIKAFAST BORDEAUX 10B-430,SEIKALIGHT ROSE R40, SEIKALIGHT VIOLET B800, 7805, SEIKAFAST MAROON460N, SEIKAFAST ORANGE 900, 2900, SEIKALIGHT BLUE C718, A612, cyanineblue 4933M, 4933GN-EP, 4940, 4973 (all manufactured by DainichiseikaColor & Chemicals Mfg. Co., Ltd.), KET Yellow 401, 402, 403, 404, 405,406, 416, 424, KET Orange 501, KET Red 301, 302, 303, 304, 305, 306,307, 308, 309, 310, 336, 337, 338, 346, KET Blue 101, 102, 103, 104,105, 106, 111, 118, 124, KET Green 201 (all manufactured by DICCorporation), Colortex Yellow 301, 314, 315, 316, P-624, 314, U10GN,U3GN, UNN, UA-414, U263, Finecol Yellow T-13, T-05, Pigment Yellow1705,Colortex Orange 202, Colortex Red101, 103, 115, 116, D3B, P-625, 102,H-1024, 105C, UFN, UCN, UBN, U3BN, URN, UGN, UG276, U456, U457, 105C,USN, Colortex Maroon601, Colortex BrownB610N, Colortex Violet600,Pigment Red 122, Colortex Blue516, 517, 518, 519, A818, P-908, 510,Colortex Green402, 403, Colortex Black 702, U905 (all manufactured bySanyo Color Works, LTD.), Lionol Yellow 1405G, Lionol Blue FG7330,FG7350, FG7400G, FG7405G, ES, ESP-S (all manufactured by TOYO INK CO.,LTD.), Toner Magenta E02, Permanent RubinF6B, Toner Yellow HG, PermanentYellow GG-02, Hostapeam BlueB2G (all manufactured by Hoechst AG, carbonblack #2600, #2400, #2350, #2200, #1000, #990, #980, #970, #960, #950,#850, MCF88, #750, #650, MA600, MA7, MA8, MA11, MA100, MA100R, MA77,#52, #50, #47, #45, #45L, #40, #33, #32, #30, #25, #20, #10, #5, #44,CF9 (all manufactured by Mitsubishi Chemical Corporation).

Viscosity Modifier

The viscosity modifier is not particularly limited and can be selectedto a suitable application. A specific example thereof is propyleneglycol.

Drying Retardant

There is no specific limitation to the drying retardant. It can besuitably selected to suit to a particular application. A specificexample thereof is glycerin.

Dispersant

There is no specific limitation to the dispersant and it can be suitablyselected to suit to a particular application. A specific example thereofis etidronic acid.

Polymerization Promoter

There is no specific limitation to the polymerization promoter and itcan be suitably selected to suit to a particular application. A specificexample thereof is N,N,N′,N′-tetramethylethylene diamine.

There is no specific limitation to the surface tension of the firstliquid and it can be selected to suit to a particular application. Forexample, the surface tension is preferably 20-45 mN/m and morepreferably 25-34 mN/m.

When the surface tension is 20 mN/m or greater, discharging stability isimproved. When the surface tension is 45 mN/m or less, filling adischarging nozzle for forming (shape-forming) with liquid is easy.

The surface tension can be measured by a surface tensiometer (automaticcontact angle DM-701, manufactured by Kyowa Interface Science Co.,LTD.), etc.

Viscosity of the first liquid has no particular limitation and can besuitably selected to suit to a particular application. The temperaturecan be adjusted. For example, viscosity is 3-20 mPa·s and morepreferably 6-12 mPa·s at 25 degrees C.

When the viscosity is 3-20 mPa·s, discharging stability can be improved.

The viscosity can be measured by, for example, a rotation viscometer(VISCOMATE VM-150 III, manufactured by TOKI SANGYO CO., LTD.) in a 25degrees C. environment.

Second Liquid

The second liquid has a composition different from the composition ofthe first liquid and has a feature to control the density of theingredient contained in the first liquid when forming athree-dimensional object. That is, in the present disclosure, the firstliquid and the second liquid are imparted to the same area and mixed toform a liquid film. The density of the curable material in the liquidfilm is adjusted by controlling the imparting position and the amount ofthe first liquid and the second liquid.

The second liquid preferably includes a solvent and other optionalingredients such as a photopolymerization initiator, a thermalpolymerization initiator, a mineral, and a cross-linking agent.

As the solvent, the same as those for the first liquid can be used.

The second liquid may further optionally include the same or differentpolymerizable monomer as in the first liquid.

However, when an additive such as a polymerization initiator is added tothe first liquid, it reacts with the curable material (e.g.,polymerizable monomer) in the first liquid, which may causedeterioration of storage stability. In such a case, if the additive isadded to the second liquid and thereafter the first liquid and thesecond liquid are mixed, the effect of the additive such aspolymerization initiator is imparted to the curable material. Therefore,the second liquid preferably includes no curable material such as apolymerization monomer.

Photopolymerization Initiator and Thermal Polymerization Initiator

As for the thermal polymerization initiator and the photopolymerizationinitiator, the same material as those for the first liquid can be used.

Although it is possible to include the thermal polymerization initiatorand the photopolymerization initiator in the first liquid, it ispreferable that the second liquid include them in terms of storagestability.

If a thermal polymerization initiator is contained in addition to aphotopolymerization initiator, the thermal polymerization initiator canpromote and complete polymerization reaction which is not completed bysolely the photopolymerization initiator. In addition, it is preferableto contain a polymerization promoter.

When the first liquid includes the thermal polymerization initiator, thethermal polymerization initiator reacts with the polymerizable monomer,which degrades storage stability of the liquid. Therefore, it ispreferable that the second liquid including no polymerizable monomerinclude a thermal polymerization initiator.

Mineral

As the mineral, the same as those for the first liquid can be used.

Cross-linking Agent Specific examples of the cross-linking agentinclude, but are not limited to, N,N′methylene bisacrylamide andpolyethylene glycol diacrylate.

Other Ingredients

The other optional ingredient has no particular limit and can beselected to suit to a particular application.

For example, the same ingredients in the first liquid can be used.

There is no specific limitation to the surface tension of the secondliquid and it can be selected to suit to a particular application. Forexample, the surface tension is preferably 20-45 mN/m and morepreferably 25-34 mN/m.

When the surface tension is 20 mN/m or greater, discharging stability isimproved. When the surface tension is 45 mN/m or less, filling adischarging nozzle for forming (shape-forming) with liquid is easy.

The surface tension can be measured by a surface tensiometer (automaticcontact angle DM-701, manufactured by Kyowa Interface Science Co.,LTD.), etc.

Viscosity of the second liquid has no particular limitation and can besuitably selected to suit to a particular application. The temperaturecan be adjusted. For example, the viscosity is 3-20 mPa·s and morepreferably 6-12 mPa·s at 25 degrees C.

When the viscosity is 3-20 mPa·s, discharging stability can be improved.

The viscosity can be measured by, for example, a rotation viscometer(VISCOMATE VM-150 III, manufactured by TOKI SANGYO CO., LTD.) in a 25degrees C. environment.

The volume of the droplet of the second liquid has no particularlimitation and can be suitably selected to suit to a particularapplication. For example, the volume is preferably 2-60 pL and morepreferably 15-30 pL. When the volume of the droplet of the second liquidis 2 pL or greater, the discharging stability is improved. When thevolume is 60 pL or less, filling a discharging nozzle for forming(shape-forming) with liquid is easy.

There is no specific limitation to the amount (percent by mass) of thesecond liquid in the liquid film formed in the first process. It can beselected to suit to a particular application. The amount is controlledbased on the imparting amount of the second liquid.

The imparting amount of the second liquid is calculated by multiplyingthe volume of the liquid droplet of the second liquid by the number ofdroplets of the second liquid.

Viscosity Change Rate

The viscosity change rate in the first liquid and the second liquidbetween the viscosity before storage (initial viscosity) and theviscosity after the liquid is left undone for two weeks at 50 degrees C.is preferably not greater than 20 percent and more preferably notgreater than 10 percent.

When the viscosity change rate is not greater than 20 percent, storagestability of the first liquid and the second liquid is appropriate. Forexample, discharging stability is good when the second liquid isimparted by an inkjet method.

The viscosity change rate between the viscosity before storage (initialviscosity) and the viscosity (post storage viscosity) after the liquidis left undone for two weeks at 50 degrees C. can be measured in thefollowing manner.

Each of the liquid of the first liquid and the second liquid is placedin a polypropylene bottle (50 mL) and left undone for two weeks in aconstant temperature tank at 50 degrees C. The liquid is taken out fromthe tank and left undone until the temperature thereof lowers to roomtemperature (25 degrees C.). Thereafter, viscosity thereof is measured.Each of viscosity of the first liquid and the second liquid before it isplaced in the tank is determined as pre-storage viscosity and viscosityof each liquid taken out from the constant temperature tank isdetermined as post-storage viscosity. The viscosity change rate iscalculated according to the following relation. The pre-storageviscosity and the post-storage viscosity can be measured by, forexample, an R type viscometer (manufactured by TOKI SANGYO CO., LTD.) at25 degree C.

Viscosity change rate (percent)={(post-storage viscosity)−(pre-storageviscosity)]/(pre-storage viscosity)}×100

Pre-storage viscosity of the first liquid and the second liquid ispreferably a viscosity of 25 mPa·s or less at 25 degrees C., morepreferably 3-20 mPa·s, and particularly preferably 3-10 mPa·s. When theviscosity is not greater than 25 mPa·s, discharging the liquid from aninkjet nozzle is stabilized.

Post-storage viscosity of the first liquid and the second liquid ispreferably 3-10 mPa·s at 25 degrees.

There is no specific limitation to the method of controlling theimparting position and the imparting amount of the first liquid and thesecond liquid. It can be suitably selected to suit to a particularapplication. For example, a control method including changing the volumeof a droplet or a control method including changing the number ofdroplets is suitable.

The method of manufacturing a three-dimensional object of the presentdisclosure includes mixing the first liquid and the second liquid toconduct reaction to cure the liquids. Therefore, since the first liquidinclude a curable material (for example, polymerizable monomer), it ispreferable that the second liquid include an additive which reacts withthe curable material and degrades storage stability.

When a material that lowers storage stability (normally viscositysubstantially increases, causing gelation) due to reaction with thecurable material in the first liquid is added to the second liquid, thefilm is gelated immediately after the film is formed duringshape-forming, which contributes to improvement on the shape-formingaccuracy.

Second Process and Second Device

In the second process, the liquid film formed in the first process iscured and the cured film (layer) is laminated, so that athree-dimensional object having different compression stress and modulusof elasticity depending on area is manufactured. In the post-curingfilm, a structure formed of the curable material is formed with otheringredients. The second process (liquid film curing process) is suitablyconducted by the following second device (film curing device).

As the second device to cure the film, an ultraviolet (UV) irradiatinglamps, electron beam irradiators, etc. are used. The liquid curingdevice preferably has a mechanism to remove ozone.

The ultraviolet irradiating lamp includes, for example, a high pressuremercury lamp and an ultra high pressure mercury lamp, and a metal halidelamp.

The ultra-high pressure mercury lamp is a point light source but if theDeepUV type combined with an optical system to have a high light useefficiency is used, the lamp is capable of emitting light in ashort-wavelength range.

Since the metal halide has a wide range of wavelength, it is suitablefor colored materials. Halogenated materials of metal such as Pb, Sn,and Fe are used therefor and can be selected to suit to absorptionspectrum of a photopolymerization initiator. The lamp for use in curinghas no particular limit and can be suitably selected to suit to aparticular application. Lamps available on the market such as H lamp, Dlamp, or V lamp, (manufactured by Fusion System) can be used.

In the present disclosure, an ultra violet-light emitting diode (UV-LED)is preferably used.

There is no specific limitation to the emitting wavelength of the LED.In general, wavelengths of 365 nm, 375 nm, 385 nm, 395, nm and 405 nmare used. Taking into account the impact on the color of an object,short wavelength irradiation is advantageous to increase absorption ofan initiator.

Since thermal energy imparted by a UV-LED during curing is less thanthat of ultraviolet irradiation lamp (high pressure mercury lamp, ultrapressure mercury lamp, metal halide lamp) for general purpose andelectron beams, the heat damage to a sample is reduced.

In particular, the hydrogels formed in the present disclosure arepresent containing water. Therefore, the feature thereof is demonstratedand the effect is significant.

Third Process and Third Device

The third process includes imparting a third liquid having a thirdcomposition forming a hard object to support a three-dimensional objectformed of the curable material cured in the second process to a sitewhere no first liquid or second liquid is imparted to form a film. Thethird process is conducted by the third device.

The same device as the first device for use in the device ofmanufacturing a three-dimensional object can be the third device toimpart the third liquid.

Third Liquid

The third liquid (also referred to as material for hard object) forms ahard object to support a three-dimensional object. The third liquidincludes a curable material, preferably a polymerization initiator, andother optional ingredients but no water or laminate viscous mineral.

The third liquid preferably has ingredients different from those of thefirst liquid and the second liquid.

The curable material is preferably a compound cured in polymerizationreaction caused by irradiation of active energy ray (ultraviolet ray,electron beam, etc.), heating, etc. For example, active energy raycurable compounds and thermally-curable compounds are suitable.

The curable material is preferably liquid at 25 degrees C.

“To impart to a site where no first liquid or second liquid is imparted”is that the site of the third liquid does not overlap the site of thefirst liquid and the second liquid. However, the third liquid site maybe adjacent to the first liquid site or the second site.

The method of imparting the third liquid is not particularly limited andcan be suitably selected to suit to a particular application.Preferably, droplets formed of the third liquid are applied to targetpositions with appropriate precision. For example, a liquid dischargingmethod is suitable. Examples of the liquid discharging method are adispenser method and an inkjet method.

The third process and device can be replaced with the following.

Using the first liquid and the second liquid for use in the firstprocess, a structure to support a three-dimensional object ismanufactured in the same manner. This support structure hassignificantly different compression stress and modulus of elasticityfrom the three-dimensional object to be formed. The support structure iscured in the second process as in the case described above. The supportstructure is removed after the three-dimensional object is formed.

Since the support structure supports a three-dimensional object whenforming the three-dimensional object and is removed thereafter, minimalstrength to support the object is enough. Alternatively, sinceincreasing removability of the support structure leads to increasingproductivity of a three-dimensional object, it is suitable to form asupport structure having low modulus of elasticity which easilycollapses by an external force.

In either case, it is suitable to form a support structure having adifferent physical properties from a target three-dimensional objectusing the first liquid and the second liquid forming the targetthree-dimensional object. Simply speaking, the ratio of the secondliquid to the first liquid in the support structure is significantlychanged from the ratio in the target three-dimensional object in a rangewhere it is possible to form the support structure.

Other Optional Process

There is no specific limitation to the other optional processes and asuitable process is selected to suit to a particular application.Specific examples thereof include, but are not limited to, a peeling-offprocess, a process of polishing a three dimensional object, and aprocess of cleaning the three-dimensional object.

In particular, it is desirable to introduce a process of smoothing thefilm cured in the third process.

The formed and cured film in the second process and the third process donot always have desired thickness in all the sites.

In the case of inkjet methods, non-discharging may occur. In bothinkjet/dispenser methods, unevenness between dots may occur. As aresult, a laminate structure obtained may lack precision.

To compensate this, for example, a film can be smoothed or mechanicallyscraped immediately after the film is formed. Alternatively, thesmoothness is detected and the amount of forming the next film isadjusted to the dot level.

The hygrogel for use in the present disclosure is relatively softbecause the target object is an internal organ. Therefore, with regardto smoothing, it is suitable to utilize mechanical smoothing immediatelyafter a film is formed.

For example, the method of mechanically smoothing a film can beconducted by, for example, a member having a blade form or a rollerform.

FIG. 24 illustrates smoothing members 20 and 21 having a roller form andFIG. 215 illustrates smoothing members 20 and 21 having a blade form.

As described above, in the method of manufacturing a three-dimensionalobject of the present disclosure, liquid is discharged and impartedthrough a fine hole in a liquid discharging method to form an image filmby film. The first liquid and the second liquid prior to curing areimparted to determined sites in predetermined amounts to form a liquidfilm having areas having locally different post-curing compressionstress and/or post-curing modulus of elasticity. When the ratio of thefirst liquid and the second liquid is changed, the mass ratio is easilychanged so that the amount of a cross-linking agent and a polymerizablepolymer per a constant volume can be controlled. For this reason, it ispossible to obtain a three-dimensional object having multiple areashaving different compression stress and modulus of elasticity.

In a typical method of manufacturing a three-dimensional object, asingle or multiple curable materials are imparted to different sites toform a three-dimensional object having portions different compressionstress and modulus of elasticity. However, in such a typicalmanufacturing method, obtained three-dimensional objects have onlycompression stresses and moduli of elasticity derived from multiplecurable materials. As a result, it is not possible to form athree-dimensional object having continuously different compressionstresses and moduli of elasticity. To the contrary, in the method ofmanufacturing a three-dimensional object of the present disclosure, thefirst liquid and the second liquid are imparted to form a liquid filmhaving multiple areas having different post-curing compression stressesand/or post-curing moduli of elasticity depending on the ratio of thefirst liquid and the second liquid to control the compression stress andthe modulus of elasticity.

By the method of manufacturing a three-dimensional object of the presentdisclosure, complex and fine soft three-dimensional objects can besimply and efficiently manufactured, which is suitable for manufacturinginternal organ models.

The method of manufacturing a three-dimensional object and the devicefor manufacturing a three-dimensional object are described below withreference to specific embodiments. The method of manufacturing ahydrogel three-dimensional object containing water as the mainingredient is described as a typical example.

The first liquid (also referred to as liquid “A”) is used as the liquidmaterial composition for a hydrogel object and the second liquid (alsoreferred to as liquid “B”) is used as ink to dilute the liquid “A”including a polymerization initiator to manufacture a hydrogel objectcontaining water as the main ingredient having different compressionstresses and moduli of elasticity depending on areas.

First, surface data or solid data of three-dimensional form designed bythree dimensional computer-aided design (CAD) or taken in by athree-dimensional scanner or a digitizer are converted into StandardTemplate Library (STL) format, which is thereafter input into alamination forming device.

Next, compression stress distribution of the three dimensional form ismeasured. There is no specific limitation to methods of measuring thecompression stress. For example, three-dimensional compression stressdistribution data are obtained by using MR Elastography (MRE), which arethereafter input into the lamination forming device. Based on thecompression stress data, the amounts of the liquid “A” and the liquid“B” to be imparted to sites corresponding to the three-dimensional dataare determined.

Based on the these input data, the direction of the three-dimensionalform to be formed is determined.

The direction is not particularly limited. Normally, the direction ischosen in which the Z direction (height direction) is the lowest.

After the direction of the three-dimensional form is determined, theprojected areas in X-Y plane, X-Z plane, and Y-Z plane of thethree-dimensional form are obtained to obtain a block form thereof. Thethus-obtained block form is sliced in the Z direction with a thicknessof a single layer. The thickness of a single layer changes depending onthe material and is preferably, for example, 20 to 60 μm. When only onethree-dimensional object is manufactured, this block form is arranged tobe placed in the center of the Z stage (i.e., table on which the objectlifted down layer by layer for each layer forming is placed).

In addition, when a plural of three-dimensional objects are manufacturedat the same time, the block forms are arranged on the Z stage. Also, theblock forms can be piled up. It is possible to automatically createthese block forms, the slice data (contour line data), and the placementon the Z stage if materials to be used are determined.

The next forming process is conducted. Different heads α and β(illustrated in FIG. 20) are moved bi-directionally (direction A anddirection B indicated by respective arrows) and discharge the liquid “A”and the liquid “B” to a determined area in a determined imparting ratioto form a dot. The liquid “A” and the liquid “B” are mixed in the dot asillustrated in FIG. 21 to obtain the pre-determined mass ratio (liquid“A”:liquid “B”).

Moreover, such dots are continuously formed to form a liquid mixtureliquid film of the liquid “A” and the liquid “B” having thepre-determined mass ratio (liquid “A”:liquid “B”) in the pre-determinedarea. Thereafter, the liquid mixture liquid film is irradiated withultraviolet (UV) ray and cured to form a hygrogel film having thepre-determined ratio (liquid “A”:liquid “B”) in the pre-determined areaas illustrated in FIG. 20.

After a single layer of the hygrogel film is formed, the stage (FIG. 20)is lowered in an amount corresponding to the thickness of the singlelayer. Again, the dots are continuously formed on the hydrogel film toform a liquid mixture liquid film of the liquid “A” and the liquid “B”having a pre-determined mass ratio (liquid “A”:liquid “B”) in apre-determined area. Thereafter, the liquid mixture liquid film of theliquid “A” and the liquid “B” is irradiated with ultraviolet (UV) rayand cured to form a hygrogel film. These processes are repeated to forma three-dimensional object as illustrated in FIG. 22.

The thus-obtained three-dimensional object (hydrogel object) containingwater as the main ingredient has different mass ratios (liquid“A”:liquid “B”) depending on the portion in the hydrogel object asillustrated in FIG. 22. Compression stress and modulus of elasticitytherein can be continuously changed.

Furthermore, the UV ray irradiator is arranged next to an inkjet headjetting a hygrogel precursor to save time to be taken for smoothingtreatment, thereby speeding up the manufacturing. If a UV-LED is used asthe UV ray irradiator, it is possible to reduce thermal energy used toirradiate an object when forming the object.

As illustrated in FIGS. 24 and 25, if smoothing members 20, 21, 22, and23 are provided adjacent to the inkjet head and the UV ray irradiator 14and 15, smoothing and controlling the thickness layer by layer arepossible, which is very useful to the manufacturing in the presentdisclosure.

Liquid Set for Manufacturing Three-Dimensional Object

The liquid set for manufacturing a three-dimensional object of thepresent disclosure includes the first liquid, the second liquid, andother optional ingredients.

The first liquid preferably includes water as the solvent and apolymerizable monomer as the curable material, more preferably amineral, and furthermore preferably a polymerization initiator.

As the polymerizable monomer, the same polymerizable monomer as in thefirst liquid in the method of manufacturing a three-dimensional objectcan be used.

The second liquid preferably includes at least one of a cross-linkingagent and a mineral and more preferably a polymerization initiator.

As the cross-linking agent, the same cross-linking agent as in thesecond liquid in the method of manufacturing a three-dimensional objectcan be used.

As the mineral, the same mineral as in the second liquid in the methodof manufacturing a three-dimensional object can be used.

As the polymerization initiator in the first liquid and the secondliquid, the same polymerization initiator as in the second liquid in themethod of manufacturing a three-dimensional object can be used.

The liquid set for manufacturing a three-dimensional object is suitablyused to manufacture various three-dimensional objects. In particular,the liquid set is suitable to manufacture complex and finethree-dimensional objects such as internal organ models.

Hydrogel Object

The hydrogel object is manufactured by the method of manufacturing athree-dimensional object of the present disclosure and at least one of80 percent compressive stress-strain and modulus of elasticity has acontinuous gradient.

As 80 percent compressive stress-strain of the hydrogel object,10-10,000 kPa is preferable. When the 80 percent compressivestress-strain is 10 kPa or greater, shape-losing during forming isprevented. When the 80 percent compressive stress-strain is 100,000 kPaor less, cracking after forming is prevented. The 80 percent compressivestress-strain can be measured by, for example, a universal tester (AG-I,manufactured by Shimadzu Corporation).

The hydrogel object is preferably biocompatible in terms of applicationto the medical field, more preferably contains water as the mainingredient, and particularly preferably has different compressionstresses and moduli of elasticity depending on the area therein.

“At least one of 80 percent compressive stress-strain and modulus ofelasticity has continuous gradients” is that the 80 percent compressivestress-strain and the modulus of elasticity are controlled for each areain the hydrogel object and at least one of the 80 percent compressivestress-strain and the modulus of elasticity constantly increases ordecreases in multiple areas.

Having generally described preferred embodiments of this invention,further understanding can be obtained by reference to certain specificexamples which are provided herein for the purpose of illustration onlyand are not intended to be limiting. In the descriptions in thefollowing examples, the numbers represent weight ratios in parts, unlessotherwise specified.

EXAMPLES

Next, the present disclosure is described in detail with reference toExamples but is not limited thereto.

Manufacturing Example 1 of First Liquid and Second Liquid

Preparation of Liquid A

Pure water was prepared by evacuating deionized water for 30 minutes.

While stirring 60 percent by mass of pure water, 6 percent by mass ofsynthesized hectorite (laponite XLG, manufactured by RockWood) having acomposition of [Mg_(5.34)Li_(0.66)Si₈O₂₀(OH)₄]Na⁻ _(−0.66) as laminateclay mineral was slowly added to the pure water followed by stirring toprepare a first liquid dispersion. Next, 0.3 percent by mass ofetidronic acid (manufactured by Tokyo Chemical Industry Co. Ltd.) as thedispersant for the synthesized hectorite was added to the first liquiddispersion to obtain a second liquid dispersion.

Next, to the second liquid dispersion, 22 percent by mass of acryloylmorpholine (ACMO, manufactured by KJ Chemicals Corporation) from which apolymerization inhibitor was removed by passing through active aluminacolumn was added as the curable material.

Furthermore, 0.2 percent by mass of N,N′-methylene bisacrylamide (MBAA,manufactured by Tokyo Chemical Industry Co. Ltd.) was added as across-linking agent. 10.2 percent by mass of glycerin (manufactured bySakamoto Yakuhin kogyo Co., Ltd.) as a drying retardant and 0.3 percentby mass of LS106 (manufactured by Kao Corporation) as a surfactant wereadmixed.

Next, after 0.4 percent by mass of a photopolymerization promotor{N,N,N′,N′-tetramethylethylene dimaine (TEMED, manufactured by TokyoChemical Industry Co. Ltd.)} was added and 0.6 percent by mass ofphotopolymerization initiator {4 percent by mass of Irgacure 184(manufactured by BASF) and 96 percent by mass of methanol} were admixedand stirred. Subsequent to the stirring and mixing, the resultant wasevacuated for ten minutes. Subsequently, impurities were removed byfiltration to obtain a uniform liquid A.

Surface tension and viscosity of the thus-obtained liquid A weremeasured in the following manner. The surface tension was 30.0 mN/m andthe viscosity was 6.5 mPA·s at 25 degrees C.

Measuring of Surface Tension

The surface tension of the thus-obtained liquid A was measured by asurface tensiometer (automatic contact angle meter DM701, manufacturedby Kyowa Interface Science Co., LTD.) according to hanging drop method.

Measuring of Viscosity

The viscosity of the liquid A was measured by a rotation viscometer(VISCOMATE VM-150 III, manufactured by TOKI SANGYO CO., LTD.) in a 25degrees C. environment.

Manufacturing Examples 2 to 9 of First Liquid and Second Liquid

Preparation of Liquid B to Liquid I

Liquid B to Liquid I were obtained in the same manner as inManufacturing Example 1 of the first liquid and the second liquid exceptthat the compositions and the amounts were changed as shown in Table 1.

Surface tension and viscosity of the thus-obtained liquid B to liquid Iwere measured in the same manner as in Manufacturing Example 1 of thefirst liquid and the second liquid.

The compositions and the properties of Liquid A to Liquid I were shownin Table 1.

TABLE 1 First liquid and second liquid A B C D E F G H I Solvent Purewater 60 87.2 60.2 60 60 66.3 — — — Toluene — — — — — — 60 85 82.6Viscosity Propylene — — — — — — 8.8 15 15 modifier alcohol Dryingretardant Glycerin 10.2 10.2 10.2 10.2 10.2 10.2 — — — Surfactant LS1060.3 0.3 0.3 0.3 0.3 0.3 — — — Dispersant etidronic acid 0.3 0.3 0.3 0.30.3 0.3 — — — Polymeri- Photopolymerization 0.6 — 0.6 0.6 0.6 0.6 0.6 —— zation initiator initiator liquid Thermal — 2 — — — — — — —polymerization initiator liquid 1 Thermal — — — — — — — — 2polymerization initiator liquid 2 Polymeri- N,N,N′,N′- 0.4 — 0.4 0.4 0.40.4 0.4 — 0.4 zation tetramethyl promoter ethylnene diamine MineralLaponite 6 — 6 6 6 — — — — Curable Acryloyl 22 — 22 22 — 22 30 — —material morpholine N,N-dimethyl — — — — 22 — — — — acrylamide OrganicN,N′-methylene 0.2 — — 0.2 0.2 0.2 0.2 — — cross- bisacrylamide linkingagent Total (percent by mass) 100 100 100 100 100 100 100 100 100Viscosity (mPa · s) 6.5 4.8 6.5 6.8 6.5 4.6 7.8 6.2 6.3 Surface tension(mN/m) 30.0 29.8 29.9 30.1 30.0 30.0 29.8 29.3 29.3

In Table 1, the product name and the manufacturing company of theingredients are as follows:

-   -   Toluene: solvent (manufactured by Wako Pure Chemical Industries,        Ltd.)    -   Propyleneglycol: viscosity modifier (manufactured by Wako Pure        Chemical Industries, Ltd.)    -   Glycerin: drying retardant (manufactured by Sakamoto Yakuhin        kogyo Co., Ltd.)    -   LS106: surfactant (manufactured by Kao Corporation)    -   Etidronic acid: dispersant (manufactured by Tokyo Chemical        Industry Co. Ltd.)    -   Photopolymerization initiator: 4 percent by mass Irgacure 184        (manufactured by BASF) and 96 percent by mass methanol    -   Thermal polymerization initiator 1: 2 percent by mass peroxo        sodium pyrosulfate and 98 percent by mass pure water    -   Thermal polymerization initiator 2:        2,2′-azobis(2,4-dimethylvaloronitrile)    -   Laponite XLG: (laminate clay mineral, manufactured by Rockwood)    -   Acryloylmorpholine (ACMO): manufactured by KJ Chemicals        Corporation    -   N, N-dimethylacrylamide (DMAA), manufactured by KJ Chemicals        Corporation    -   N, N′-methylene bisacrylamide (MBAA): manufactured by Tokyo        Chemical Industry Co. Ltd.    -   N, N, N′,N′-tetramethylethylene dimaine (TEMED)—polymerization        promoter (manufactured by Tokyo Chemical Industry Co. Ltd.)

Example 1

Liquid A was used as the first liquid and Liquid B was used as thesecond liquid.

A three-dimensional object as hydrogel object containing water as themain ingredient as illustrated in FIG. 1 was obtained by conducting thefollowing process 1 to process 4 using the liquid A and the liquid B.

1. The liquid A and the liquid B were mixed with a mass ratio of 2:1(liquid A:liquid B) and poured in a mold having a dimension of 30 mm(depth)×30 mm (width)×8 mm (height) until the height of the mixturereached 2 mm, that is, 7.2 cube centi-meter. The mixture was left undonefor 6 hours at 27 degrees C. to manufacture the first layer of ahydrogel.

2. Next, the liquid A and the liquid B were mixed with a mass ratio of1:1 (liquid A:liquid B) and 7.2 cube centi-meter thereof was poured onthe first layer in the mold having a dimension of 30 mm (depth)×30 mm(width)×8 mm (height). The mixture was left undone for 6 hours at 27degrees C. to manufacture a second layer.

3. Next, the liquid A and the liquid B were mixed with a mass ratio of1:2 (liquid A:liquid B) and 7.2 cube centi-meter thereof was poured onthe second layer in the mold having a dimension of 30 mm (depth)×30 mm(width)×8 mm (height). The mixture was left undone for 6 hours at 27degrees C. to manufacture a third layer.

4. Finally, the liquid A and the liquid B were mixed with a mass ratioof 1:3 (liquid A:liquid B) and 7.2 cube centi-meter thereof was pouredon the second layer in the mold having a dimension of 30 mm (depth)×30mm (width)×8 mm (height). The mixture was left undone for 12 hours at 27degrees C. to manufacture a fourth layer to obtain a three-dimensionalobject (hydrogel object) containing water as the main ingredient.

The structure of the thus-obtained hygrogel is schematically shown inTable 1.

To measure modulus of elasticity of each layer of the three-dimensionalobject (hydrogel object) containing water of the thus-obtainedfour-layer structure as the main ingredient, the three-dimensionalobject containing water as the main ingredient was placed on the side asillustrated in FIG. 2 and cylindrical metal having a diameter of 1 mmwas pressed into the hydrogel object containing water as the mainingredient from above using a compression tester. The stress wasmeasured at three points N1, N2, and N3 for each layer by thecompression tester. Thus, the modulus of elasticity under 20 percentcompression was measured for each layer. The results are shown in Table2.

TABLE 2 Mass ratio 20 percent modulus of elasticity (MPa) Layer number(A:B) N1 N2 N3 1 2:1 0.26 0.24 0.26 2 1:1 0.10 0.09 0.09 3 1:2 0.03 0.030.03 4 1:3 0.01 0.01 0.01

As seen in the results of Table 2, when the mass ratio of the liquid Aand the liquid B is changed for each layer, each layer is found to havea different modulus of elasticity.

The degree of modulus of elasticity is shown by shading. As the modulusof elasticity increases, the density (shade) increases.

When a hydrogel layer was overlaid while changing the mass ratio (liquidA:liquid B) of the liquid A and the liquid B in the mold as illustratedin FIG. 1, a three-dimensional object (hygrogel object) containing wateras the main ingredient free of layer peeling off was obtained.Furthermore, when the modulus of elasticity was measured as illustratedin FIG. 2, it was found that a hydrogel object containing water as themain ingredient which had multiple areas having different values ofmodulus of elasticity as shown in Table 2 was obtained.

Example 2

The liquid A (forming liquid) was used as the first liquid and theliquid B (diluting liquid) was used as the second liquid.

The inkjet heads (MH5420, manufactured by Ricoh Industry Company, Ltd.)were filled with the liquid A and the liquid B and discharged them in300 dpi×300 dpi. The volume of droplets discharged was controlled tochange the mass ratio (liquid A:liquid B) as illustrated in FIG. 3 toobtain a three-dimensional object (hydrogel object) containing water asthe main ingredient. FIG. 3 is a diagram illustrating the mixing ratiodistribution in which the volume of the droplets of the liquid A and theliquid B in a single area in the three-dimensional object (hydrogelobject) containing water as the main ingredient.

To be specific, four heads were used for the first liquid and anotherfour was used for the second liquid to discharge the liquid A and theliquid B. The total amount of the liquid imparted on the single area wascontrolled to be 144 pL.

For example, the liquid volume was changed in such a manner that theratio of the volume of a droplet of the liquid A and the volume of adroplet of the liquid B was 24 pL:120 pL, 48 pL:96 pL, and 72 pL:72 pLto form a film including a hydrogel. Thereafter, the film was cured bylight emitted by an ultraviolet ray irradiaor (SPOT CURE SP5-250DB,manufactured by USHIO INC.) in a light amount of 350 mJ/cm². A hundredlayers were formed in the same manner and cured to manufacture athree-dimensional object (hydrogel object) containing water as the mainingredient. Thus, a hydrogel object containing water as the mainingredient with a dimension of 20 mm (depth)×20 mm (width)×2 mm (height)free of layer peel-off was obtained.

The modulus of elasticity under 20 percent compression of the hydrogelobject containing water as the main ingredient was measured. The modulusof elasticity was measured by using a universal tester (AG-I,manufactured by Shimadzu Corporation), a load cell 1 kN, and compressionjig for 1 kN while pressing cylindrical metal having a diameter of 1 mminto the hydrogel object containing water as the main ingredient. Thestress against the compression applied to the load cell was recorded ina computer and the stress against displacement was plotted to measurethe modulus of elasticity. In addition, the pressed-in area was an area(x,y) of the hydrogel object containing water as the main ingredient andthe modulus of elasticity was measured for each area of 2 mm×2 mm whilechanging both x and y from 0 to 20 in FIG. 3.

The measuring results of modulus of elasticity are shown in Table 3 andFIG. 4. FIG. 4 is a diagram illustrating the values of modulus ofelasticity for each area of 2 mm×2 mm in the hydrogel object containingwater as the main ingredient illustrated in FIG. 3. The area of film ofeach mass ratio (liquid A:liquid B) of FIG. 3 corresponds to the area ofthe value of the modulus of elasticity under 20 percent compression inFIG. 4. The modulus of elasticity under 20 percent compression is agradient of the compression stress under 20 percent compression.

As seen in the results of Table 3 and FIG. 4, when the volumes ofdroplets of the liquid A and the liquid B were changed to control themass ratio (liquid A:liquid B), a three-dimensional object (hydrogelobject) containing water as the main ingredient was manufactured havingmultiple areas with continuously different modulus of elasticity in alayer.

Example 3

The liquid A (forming liquid) was used as the first liquid and theliquid B (diluting liquid) was used as the second liquid.

The inkjet heads (MH5420, manufactured by Ricoh Industry Company, Ltd.)were filled with the liquid A and the liquid B and discharged them in300 dpi×300 dpi. The number of droplets to be discharged was changed tochange the mass ratio (liquid A:liquid B) in each area as illustrated inFIG. 5 to manufacture a three-dimensional object (hydrogel object)containing water as the main component. FIG. 5 is a diagram illustratingthe mixing ratio distribution in which the number of the droplets of theliquid A and the liquid B in a single area in the three-dimensionalobject (hydrogel object) containing water as the main component.

To be specific, four heads were used for the first liquid and anotherfour was used for the second liquid to discharge the liquid A and theliquid B. The total amount of the liquid imparted on the single area wascontrolled to be 144 pL.

The volume of a single droplet was determined to be 36 pL and fourdroplets were discharged for the single area. For example, the number ofdroplets was controlled in such a manner that the ratio of the number ofdroplets of the liquid A and the number of droplets of the liquid B in asingle area was 1:3, 2:2, 3:1, and 4:0 to form a film including athree-dimensional object (hydrogel object) containing water as the mainingredient. Thereafter, the film was cured by light emitted by anultraviolet ray irradiaor (SPOT CURE SP5-250DB, manufactured by USHIOINC.) in a light amount of 350 mJ/cm². A hundred layers were formed andcured in the same manner to manufacture a three-dimensional object(hydrogel object) containing water as the main ingredient. Thus, ahydrogel object containing water as the main ingredient with a dimensionof 20 mm (depth)×20 mm (width)×2 mm (height) free of layer peel-off wasobtained.

The modulus of elasticity under 20 percent compression of thethus-obtained hydrogel object containing water as the main component wasmeasured.

The modulus of elasticity under 20 percent compression was measured inthe same manner as described in Example 2. The measuring results areshown in Table 3 and FIG. 6.

FIG. 6 is a diagram illustrating the values of modulus of elasticity foreach area of 2 mm×2 mm in the hydrogel object containing water as themain ingredient illustrated in FIG. 5.

The area of film of each mass ratio (liquid A:liquid B) of FIG. 5corresponds to the area of the values of the modulus of elasticity under20 percent compression in FIG. 6.

As seen in the results of Table 3 and FIG. 6, when the mass ratio(liquid A:liquid B) of the liquid A and the liquid B, namely, the numberof droplets of the liquid A and the liquid B, was changed as illustratedin FIG. 5, the modulus of elasticity under 20 percent compression waseasily changed as illustrated in FIG. 6.

Unlike Example 1, a three-dimensional object (hydrogel object)containing water as the main ingredient was manufactured having multipleareas with continuously different modulus of elasticity in a layer.

Example 4

The liquid F (forming liquid) was used as the first liquid and theliquid B (diluting liquid) was used as the second liquid.

The inkjet heads (MH5420, manufactured by Ricoh Industry Company, Ltd.)were filled with the liquid F and the liquid B and discharged them in300 dpi×300 dpi. The volume of a droplet of discharged was controlled tochange the mass ratio (liquid F:liquid B) as illustrated in FIG. 7 toobtain a three-dimensional object (hydrogel object) containing water asthe main ingredient. FIG. 7 is a diagram illustrating the mixing ratiodistribution in which the volume of the droplet of the liquid F and theliquid B in a single area in the three-dimensional object (hydrogelobject) containing water as the main ingredient.

To be specific, four heads were used for the first liquid and anotherfour was used for the second liquid to discharge the liquid F and theliquid B. The total amount of the liquid imparted on the single area wascontrolled to be 144 pL.

For example, the liquid droplet volume was changed in such a manner thatthe ratio of the volume of a droplet of the liquid F and the volume of adroplet of the liquid B was 24 pL:120 pL, 48 pL:96 pL, and 72 pL:72 pLto form a liquid film including a hydrogel containing water as the mainingredient. Thereafter, the liquid film was cured by light emitted by anultraviolet ray irradiaor (SPOT CURE SP5-250DB, manufactured by USHIOINC.) in a light amount of 350 mJ/cm². A hundred layers were formed andcured in the same manner to manufacture a three-dimensional object(hydrogel object) containing water as the main ingredient. Thus, ahydrogel object containing water as the main ingredient with a dimensionof 20 mm (depth)×20 mm (width)×2 mm (height) free of layer peel-off wasobtained.

The modulus of elasticity under 20 percent compression of thethus-obtained hydrogel object containing water as the main ingredientwas measured in the same manner as in Example 2. The measuring resultsof the modulus of elasticity are shown in Table 3 and FIG. 8. FIG. 8 isa diagram illustrating the values of modulus of elasticity for each areaof 2 mm (depth)×2 mm (width) in the hydrogel object containing water asthe main ingredient illustrated in FIG. 7. The area of film of each massratio (liquid F:liquid B) of FIG. 7 corresponds to the area of the valueof the modulus of elasticity under 20 percent compression in FIG. 8.

As seen in the results of Table 3 and FIG. 8, when the mass ratio(liquid F:liquid B) of the liquid F and the liquid B was changed, themodulus of elasticity was changed.

Unlike Example 1, a three-dimensional object (hydrogel object)containing water as the main ingredient was manufactured having multipleareas with continuously different modulus of elasticity in a layer.However, it was found that, without laponite XLG, the obtainedthree-dimensional object contained a hygrogel having extremely lowmodulus of elasticity as the main ingredient.

Example 5

The liquid A (forming liquid) was used as the first liquid and theliquid B (diluting liquid) was used as the second liquid.

The liquid A and the liquid B were mixed changing the mass ratio (liquidA:liquid B) of the liquid A and the liquid B and the liquid mixture waspoured in a mold having a dimension of 30 mm (depth)×30 mm (width)×8 mm(height). The mixture was left undone for 12 hours at 27 degrees C. tomanufacture a three-dimensional object (hydrogel object) containingwater as the main ingredient.

According to the same measuring manner as modulus of elasticity under 20percent compression described in Example 1, compression stress under 70percent compression (70 percent compressive stress-strain), compressionstress under 80 percent compression (80 percent compressivestress-strain), and modulus of elasticity under 20 percent compressionwere measured.

Toughness of a three-dimensional object (hydrogel compression)containing water as the main ingredient can be evaluated by thecompression stress under 70 percent compression and 80 percentcompression. The results are shown in Table 9.

As described in FIG. 9, as the ratio of the liquid A increased, thecompression stress of a three-dimensional object (hydrogel object)containing water as the main ingredient was found to increase. Namely,it was found that, when the mass ratio of the liquid A and the liquid Bwas changed, the compression stress of a three-dimensional object(hydrogel object) containing water as the main ingredient was easilychanged.

It was also found that, when the imparting amount of each liquid of theliquid set for manufacturing a three-dimensional object was controlled,it was possible to form a three-dimensional object (hydrogel object)containing water as the main ingredient and having multiple areas havingdifferent values of post-curing modulus of elasticity.

Example 6

The liquid C (forming liquid) was used as the first liquid and theliquid D (diluting liquid) was used as the second liquid.

The liquid C and the liquid D were mixed changing the mass ratio (liquidC:liquid D) of the liquid C and the liquid D as shown in Table 3 in thesame manner as described in Example 1 and the liquid mixture was pouredin a mold having a dimension of 30 mm (depth)×30 mm (width)×8 mm(height). The mixture was left undone for 12 hours at 27 degrees C. tomanufacture a three-dimensional object (hydrogel object) containingwater as the main ingredient. The compression stress under 70 percentcompression, the compression stress under 80 percent compression, andthe modulus of elasticity 20 percent compression of the thus-obtainedhydrogel object containing water as the main ingredient were measured inthe same manner as in Example 1. The measuring results are shown inTable 3 and FIG. 10.

As described in FIG. 10, as the ratio of the liquid D increased, thecompression stress of a three-dimensional object (hydrogel object)containing water as the main ingredient also increased. Namely, it wasfound that, when the mass ratio of the liquid C and the liquid D waschanged, the compression stress and modulus of elasticity of athree-dimensional object (hydrogel object) containing water as the mainingredient were easily changed.

It was also found that, when the imparting amount of each liquid of theliquid set for manufacturing a three-dimensional object was controlled,it was possible to form a three-dimensional object (hydrogel object)containing water as the main ingredient having multiple areas havingdifferent values of post-curing modulus of elasticity.

Example 7

The liquid A (forming liquid) was used as the first liquid and theliquid E (diluting liquid) was used as the second liquid.

The liquid A and the liquid E were mixed changing the mass ratio (liquidA:liquid E) of the liquid A and the liquid E and the liquid mixture waspoured in a mold having a dimension of 30 mm (depth)×30 mm (width)×8 mm(height). The mixture was left undone for 12 hours at 27 degrees C. tomanufacture a three-dimensional object (hydrogel object) containingwater as the main ingredient. The compression stress under 70 percentcompression, the compression stress 80 percent compression, and themodulus of elasticity under 20 percent compression of the thus-obtainedhydrogel object containing water as the main ingredient were measured inthe same manner as in Example 5. The measuring results are shown inTable 3 and FIG. 11.

As described in FIG. 11, as the ratio of the liquid E increased, thecompression stress of a three-dimensional object (hydrogel object)containing water as the main ingredient decreased. Namely, it was foundthat, when the mass ratio of the liquid A and the liquid E was changed,the compression stress of a three-dimensional object (hydrogel object)containing water as the main ingredient was easily changed.

It was also found that, when the imparting amount of each liquid of theliquid set for manufacturing a three-dimensional object was controlled,it was possible to form a three-dimensional object (hydrogel object)containing water as the main ingredient having multiple areas havingdifferent values of post-curing modulus of elasticity.

Example 8

A non-contact dispenser (Cyber Jet 2, manufactured by MUSASHIENGINEERING INC.) was used with twin heads. When Cyber Jet 2 was usedwith twin heads, the mixing ratio of two kinds of liquids can beprecisely managed by the number of jetting.

The liquid A (forming liquid) was used as the first liquid and theliquid B (diluting liquid) was used as the second liquid.

The dispenser 1 discharged the liquid A and the dispenser 2 dischargedthe liquid B at a rate of 0.03 mg per droplet The number of droplets tobe discharged was changed to change the mass ratio (liquid A:liquid B)as illustrated in FIG. 12 to manufacture a three-dimensional object(hydrogel object) containing water as the main ingredient. FIG. 12 is adiagram illustrating the mixing ratio distribution in which the volumeof the droplets of the liquid A and the liquid B in a single area in thethree-dimensional object (hydrogel object) containing water as the mainingredient.

To be specific, the mass of the liquid discharged to the single area of5 mm (depth)×5 mm (width)×5 mm (height) was 0.09 mg, namely, equivalentto the amount of three droplets. For example, the discharging volume ofthe liquid droplet was changed in such a manner that the ratio of thenumber of liquid droplets of the liquid A to the number of liquiddroplets of the liquid B was 3:0, 2:1, and 1:2. The liquid mixture wasirradiated and cured with light emitted by an ultraviolet ray irradiaor(SPOT CURE SP5-250DB, manufactured by USHIO INC.) in a light amount of350 mJ/cm² to form a three-dimensional object (hydrogel object). Thus,the three-dimensional object (hydrogel object) containing water as themain ingredient with a dimension of 15 mm (depth)×15 mm (width)×5 mm(height) free of layer peel-off was obtained. The modulus of elasticityunder 20 percent compression of the hydrogel object containing water asthe main ingredient was measured in the same manner as in Example 2. Inaddition, the pressed-in area of a cylindrical metal having a diameterof 1 mm was each area (x, y) of 2.5 mm×2.5 mm of the hydrogel objectcontaining water as the main ingredient while changing both x and y from0 to 15. The measuring results are shown in Table 3 and FIG. 13.

The area of the film of each mass ratio (liquid A:liquid B) of FIG. 12corresponds to the area of the value of the modulus of elasticity under20 percent compression in FIG. 13.

As seen in the results of FIG. 13, when the mass ratio (liquid A:liquidB) of the liquid A and the liquid B, namely, the number of droplets, waschanged as illustrated in FIG. 12, the modulus of elasticity was easilychanged as illustrated in FIG. 13.

Unlike Example 1, a three-dimensional object (hydrogel object)containing water as the main ingredient was manufactured having multipleareas with continuously different compression stress in a layer.

Example 9

The liquid G (forming liquid) was used as the first liquid and theliquid H (diluting liquid) was used as the second liquid.

The inkjet head (MH5420, manufactured by Ricoh Industry Company Ltd.)was filled with the liquid G and the liquid H and discharged them. Thevolume of droplets discharged was changed to change the mass ratio(liquid G:liquid H) as illustrated in FIG. 14 to obtain an oil gel. FIG.14 is a diagram illustrating the mixing ratio distribution in which thevolume of the droplets of the liquid G and the liquid H in a single areain the oil gel.

To be specific, four inkjet heads (MH5420, manufactured by RicohIndustry Company Ltd.) were filled with the liquid G and another fourwere filled with the liquid H to discharge them. The total amount of theliquid imparted on the single area was controlled to be 144 pL.

For example, the liquid volume was changed in such a manner that theratio of the volume of a droplet of the liquid G and the volume of adroplet of the liquid H was 24 pL:120 pL, 48 pL:96 pL, and 72 pL:72 pLto form a liquid film of an oil gel. Thereafter, the liquid film wascured by light emitted by an ultraviolet ray irradiaor (SPOT CURESP5-250DB, manufactured by USHIO INC.) in a light amount of 350 mJ/cm².A hundred layers were formed and cured in the same manner to manufacturea three-dimensional oil gel object. Thus, the three-dimensional oil gelwith a dimension of 20 mm (depth)×20 mm (width)×2 mm (height) free oflayer peel-off was obtained.

The modulus of elasticity under 20 percent compression of the oil gelwas measured in the same manner as described in Example 2. The measuringresults are shown in Table 3 and FIG. 15. FIG. 15 is a diagramillustrating the values (MPa) of the modulus of elasticity for each areaof 2 mm (depth)×2 mm (width) in the oil gel illustrated in FIG. 14. Thearea of film of each mass ratio (liquid G:liquid H) of FIG. 14corresponds to the area of the value of the modulus of elasticity under20 percent compression in FIG. 15.

It is found that different modulus of elasticity can be obtained bychanging the mixing ratio of the liquid G and the liquid H.

Example 10

The liquid G (forming liquid) was used as the first liquid and theliquid I (diluting liquid) was used as the second liquid. The inkjethead (MH5420, manufactured by Ricoh Industry Company, Ltd.) was filledwith the liquids and discharged them in the same manner as in Example 2.

The volume of droplets discharged was changed to change the mass ratio(liquid G:liquid I) as illustrated in FIG. 16 to obtain an oil gel. FIG.16 is a diagram illustrating the mixing ratio distribution in which thevolume of the droplets of the liquid G and the liquid I in a single areain the oil gel.

To be specific, four inkjet heads (MH5420, manufactured by RicohIndustry Co., Ltd.) were filled with the liquid A and another fourinkjet heads were filled with the liquid B to discharge them. The totalamount of the liquid imparted on the single area was controlled to be144 pL. For example, the liquid volume was changed in such a manner thatthe ratio of the volume of a droplet of the liquid G and the volume of adroplet of the liquid I was 24 pL:120 pL, 48 pL:96 pL, and 72 pL:72 pLto form a liquid film of an oil gel. Thereafter, the liquid film wascured by light emitted by an ultraviolet ray irradiaor (SPOT CURESP5-250DB, manufactured by USHIO INC.) in a light amount of 350 mJ/cm².A hundred layers were formed and cured in the same manner to manufacturea three-dimensional oil gel object. Thus, the three-dimensional oil gelwith a dimension of 20 mm (depth)×20 mm (width)×2 mm (height) free oflayer peel-off was obtained.

The modulus of elasticity under 20 percent compression of the oil gelwas measured in the same manner as described in Example 2. The measuringresults are shown in Table 3 and FIG. 17. FIG. 17 is a diagramillustrating the values (MPa) of the modulus of elasticity for each areaof 2 mm (depth)×2 mm (width) in the oil gel illustrated in FIG. 16. Thearea of film of each mass ratio (liquid G:liquid I) of FIG. 16corresponds to the area of the value of the modulus of elasticity under20 percent compression in FIG. 17.

It is found that different modulus of elasticity can be obtained bychanging the mixing ratio of the liquid G and the liquid I.

The degree of polymerization of the oil gel obtained in the area of theliquid G:the liquid I=1:0 and the area of the liquid G:the liquid I=1:1was measured by a thermal mass analyzer (Thermoplus TG8120, manufacturedby Rigaku Corporation). To be specific, after a cube of 2 mm (depth)×2mm (width)×2 mm (height) was cut out from the oil gel in the areas, thepolymer containing ratio was measured by thermal mass analysis to obtainthe degree of polymerization. While the degree of polymerization was 92percent in the area of the liquid G:the liquid I=1:0, the degree ofpolymerization was increased to 97 percent in the area of the liquidG:the liquid I=1:1. Therefore, the effect of the thermal polymerizationinitiator was confirmed.

Comparative Example 1

The liquid A (forming liquid) was used as the first liquid and theliquid B (diluting liquid) was used as the second liquid.

The inkjet head (MH5420, manufactured by Ricoh Industry Company, Ltd.)was filled with the liquid A and the liquid B and discharged them in 300dpi×300 dpi in the same manner as in Example 2. The volume of dropletsdischarged, that is, the mass ratio (liquid A:liquid B) was set to be1:1 to manufacture a three-dimensional object (hydrogel object)containing water as the main ingredient. FIG. 18 indicates that thevolume ratio of the droplets of the liquid A and the liquid B in asingle area in the three-dimensional object (hydrogel object) containingwater as the main ingredient is 1:1.

To be specific, four inkjet heads (MH5420, manufactured by RicohIndustry Co., Ltd.) were filled with the liquid A and another four wasfilled with the liquid B to discharge both liquids. The total amount ofthe liquid imparted on the single area was controlled to be 144 pL. Theliquid volume was maintained constant in such a manner that the ratio ofthe volume of a droplet of the liquid A and the volume of a droplet ofthe liquid B was 72 pL:72 pL to form a liquid film of athree-dimensional object (hydrogel object) containing water as the mainingredient. Thereafter, the liquid film was cured by light emitted by anultraviolet ray irradiaor (SPOT CURE SP5-250DB, manufactured by USHIOINC.) in a light amount of 350 mJ/cm². Such a liquid film was formedhundred times and cured in the same manner to manufacture athree-dimensional object (hydrogel object) containing water as the mainingredient. Thus, a hydrogel object containing water as the mainingredient with a dimension of 20 mm (depth)×20 mm (width)×2 mm (height)free of layer peel-off was obtained.

The modulus of elasticity under 20 percent compression of thethus-obtained hydrogel object containing water as the main ingredientwas measured in the same manner as in Example 2. The measuring resultsare shown in Table 3 and FIG. 19.

The area of film of each mixing ratio of FIG. 18 corresponds to the areaof the value of the modulus of elasticity in FIG. 19.

When the mass ratio (liquid A:liquid B) of the liquid A and the liquid Bwas kept constant, a uniform three-dimensional object (hydrogel object)containing water as the main ingredient was formed having a uniform 20percent modulus of elasticity.

Unlike Examples 2 and 3, a three-dimensional object (hydrogel object)containing water as the main ingredient with multiple areas havingdifferent values of modulus of elasticity was not formed.

TABLE 3 20 percent 70 percent 80 percent Mass ratio modulus ofcompression compression First Second (first liquid:second elasticitystress stress liquid liquid liquid) (MPa) (MPa) (MPa) Example 1 liquidliquid 1:3 0.01 — — A B 1:2 0.03 — — 1:1 0.09-0.10 — — 2:1 0.24-0.26 — —2 liquid liquid 1:3 0.01 — — A B 1:2 0.02-0.03 — — 1:1 0.03-0.10 — — 2:10.13-0.28 — — 3 liquid liquid 1:3 0.01 — — A B 1:1 0.03-0.12 — — 3:10.34-0.42 — — 4:0 0.46-0.57 — — 4 liquid F liquid 1:3 0.003-0.004 — — B1:2 0.007-0.009 — — 1:1 0.01 — — 2:1 0.02-0.04 — — 5 liquid liquid 1:20.13 0.051 0.15 A B 1:1 0.27 0.18 0.49 2:1 0.13 0.45 1 6 liquid liquid1:2 0.23 0.52 1.5 C D 1:1 0.18 0.44 1.2 2:1 0.12 0.27 0.8 7 liquidliquid E 1:2 0.12 0.26 0.9 A 1:1 0.16 0.38 1.2 2:1 0.2  0.49 1.5 8liquid liquid 1:2 0.03-0.08 — — A B 1:1 0.20-0.27 — — 2:1 0.31-0.37 — —9 liquid liquid 1:0 0.75-0.84 — — G H 2:1 0.45-0.55 — — 1:1 0.16-0.23 —— 1:2 0.60-0.10 — — 10 liquid liquid I 1:0 0.75-0.83 — — G 2:1 0.48-0.58— — 1:1 0.21-0.27 — — 1:2 0.09-0.13 — — Comparative 1 liquid liquid 1:10.02-0.04 — — Example A B — —

Example 11

Liquid A was used as the first liquid and Liquid B was used as thesecond liquid.

Like Example 2, the liquid A and the liquid B were laminated in such amanner while forming an area having a mixing ratio (liquid A:liquid B)of 2:1 and an area having a mixing ratio (liquid A:liquid B) of 1:2 toform a three-dimensional object of 20 mm (depth)×20 mm (width)×20 mm(height) using the device illustrated in FIG. 20. The manufacturingconditions are according to Example 2.

Example 12

A three-dimensional object of 20 mm (depth)×20 mm (width)×20 mm (height)was manufactured in the same manner as in Example 11 using the deviceillustrated in FIG. 23.

The light source for use in the device illustrated in FIG. 23 was aUV-LED (SubZero-LED 365 nm, manufactured by Integration) and the lightamount was adjusted to 350 mJ/cm².

Example 13

A three-dimensional object of 20 mm (depth)×20 mm (width)×20 mm (height)was manufactured in the same manner as in Example 11 using the deviceillustrated in FIG. 24. In FIG. 24, reference numerals 10, 11, 12, 16,17, and 18 represent a manufacturing device, an ink jetting head unitfor liquid for forming a three-dimensional object, an ink jetting headunit for liquid for dilution, a support substrate to support athree-dimensional object, a stage, and a three-dimensional object,respectively.

The light source for use in the device illustrated in FIG. 24 was aUV-LED (SubZero-LED 365 nm, manufactured by Integration) and the lightamount was adjusted to 350 mJ/cm².

The smoothing member was reversely rotated.

The three-dimensional objects of Examples 11 to 13 were evaluated asfollows. Forming Property of Three-dimensional Object

The form of the entire three-dimensional object and whether there wasdeficiency in areas having different ingredients were visually checked.

Evaluation Criteria

A: Good B: Fair C: Bad

Error in Horizontal Direction and Error in Perpendicular Direction

As illustrated in FIG. 26, the dimensions of the three-dimensionalobject formed in Examples 11 to 13 were measured at 10 positions in thehorizontal direction and the perpendicular direction. The degree ofdeviation of the 10 positions was obtained and evaluated.

Evaluation Criteria

A: Good B: Fair C: Bad

TABLE 4 Forming property of Error in three-dimensional Error inhorizontal perpendicular object direction direction Example 11 A B to AB Example 12 A A B Example 13 A A A

Example 14

Liquid A was used as the first liquid and Liquid B was used as thesecond liquid.

The three-dimensional object and the support structure illustrated inFIG. 27 were formed using the device illustrated in FIG. 23.

The area of the three-dimensional object was formed with the mixingratio of the liquid A and the liquid B of 2:1 and the area of thesupport structure was formed with the mixing ratio of the liquid A andthe liquid B of 1:5.

When forming the support structure, the area thereof kept at leastminimal strength to support the three-dimensional object.

After the forming, as illustrated in FIG. 28, the three-dimensionalobject 30 was taken out while breaking the support structures 31 and 32to separate it from the three-dimensional object.

Embodiments of the present disclosure are, for example, as follows.

1. A method of manufacturing a three-dimensional object includesimparting a first liquid having a first composition including a solventand a curable material and a second liquid having a second compositionto form a liquid film, curing the liquid film and repeating theimparting and the curing to obtain the three-dimensional object, whereinthe imparting position and the imparting amount of each of the firstliquid and the second liquid are controlled in such a manner that theliquid film includes multiple areas where post-curing compression stressand/or post-curing modulus of elasticity are different.

2. The method according to 1 mentioned above, wherein the impartingposition of the first liquid matches the imparting position of thesecond liquid.

3. The method according to 1 or 2 mentioned above, wherein the firstliquid and the second liquid are imparted in a liquid dischargingmethod.

4. The method according to any one of 1 to 3 mentioned above, whereinthe imparting amount of the first liquid and the imparting amount of thesecond liquid are controlled based on the volume of a droplet or thenumber of droplets to be imparted.

5. The method according to any one of 1 to 4 mentioned above, whereinthe second liquid includes no curable material.

6. The method according to any one of 1 to 5 mentioned above, whereinthe imparting position and the imparting amount of each of the firstliquid and the second liquid are controlled to further form a supportstructure to support the three-dimensional object.

7. A liquid set for manufacturing a three-dimensional object includes afirst liquid having a first composition including a solvent and acurable material and a second liquid having a second composition.

8. The liquid set according to 7 mentioned above, wherein the solventincludes water, the curable material includes a polymerizable monomer,and the first liquid further includes a mineral.

9. The liquid set according to 7 or 8 mentioned above, wherein thesecond liquid includes at least one of a cross-linking agent and amineral.

10. The liquid set according to any one of 7 to 9 mentioned above,wherein at least one of the first liquid and the second liquid includesa polymerization initiator.

11. The liquid set according to any one of 7 to 10 mentioned above,wherein the second liquid includes a different polymerizable monomerfrom the polymerizable monomer included in the first liquid.

12. The liquid set in any one of 7 to 10 mentioned above, wherein thesecond liquid includes the same polymerizable monomer as thepolymerizable monomer included in the first liquid.

13. The liquid set according to any one of 7 to 10 mentioned above,wherein the second liquid includes no curable material.

14. The liquid set according to any one of 7 to 13 mentioned above,further comprising a third liquid having a third composition.

15. A method of manufacturing a three-dimensional object includesimparting the first liquid and the second liquid of the liquid set ofany one of 7 to 13 mentioned above to form a liquid film and curing theliquid film.

16. A device for manufacturing a three-dimensional object includes animparting device to impart the first liquid and the second liquid of theliquid set of any one of 7 to 13 mentioned above to form a liquid filmand a curing device to cure the liquid film.

17. The device according to 16 mentioned above, wherein the curingdevice includes an ultraviolet light-emitting diode.

18. The device according to 16 or 17 mentioned above, further includinga smoothing device to smooth the liquid film cured.

19. A gel object includes a solvent and a polymer, wherein at least oneof 80 percent compressive stress-strain and modulus of elasticity has acontinuous gradient.

20. The gel object according to 19 mentioned above, wherein 80 percentcompressive stress-strain is 10-10,000 kPa.

According to the present invention, the method of manufacturing athree-dimensional object capable of simply and efficiently manufacturinga three-dimensional object having multiple areas where compressionstress and modulus of elasticity are different.

Having now fully described embodiments of the present invention, it willbe apparent to one of ordinary skill in the art that many changes andmodifications can be made thereto without departing from the spirit andscope of embodiments of the invention as set forth herein.

What is claimed is:
 1. A method of manufacturing a three-dimensionalobject comprising: imparting a first liquid having a first compositionincluding a solvent and a curable material and a second liquid having asecond composition to form a liquid film; curing the liquid film; andrepeating the imparting and the curing to obtain the three-dimensionalobject, wherein an imparting position and an imparting amount of each ofthe first liquid and the second liquid are controlled in such a mannerthat the liquid film includes multiple areas where at least one ofpost-curing compression stress and post-curing modulus of elasticity isdifferent.
 2. The method according to claim 1, wherein the impartingposition of the first liquid matches the imparting position of thesecond liquid.
 3. The method according to claim 1, wherein the impartingis conducted utilizing a liquid discharging method.
 4. The methodaccording to claim 1, wherein the imparting amount of the first liquidand the imparting amount of the second liquid are controlled based on avolume of a droplet or a number of droplets to be imparted.
 5. Themethod according to claim 1, wherein the second liquid includes nocurable material.
 6. The method according to claim 1, wherein theimparting position and the imparting amount of each of the first liquidand the second liquid are controlled to further form a support structureto support the three-dimensional object.
 7. A liquid set formanufacturing a three-dimensional object comprising: a first liquidhaving a first composition including a solvent and a curable material;and a second liquid having a second composition.
 8. The liquid setaccording to claim 7, wherein the solvent includes water, the curablematerial includes a polymerizable monomer, and the first liquid furtherincludes a mineral.
 9. The liquid set according to claim 7, wherein thesecond liquid includes at least one of a cross-linking agent and amineral.
 10. The liquid set according to claim 7, wherein at least oneof the first liquid and the second liquid includes a polymerizationinitiator.
 11. The liquid set according to claim 7, wherein the secondliquid includes a different polymerizable monomer from the polymerizablemonomer included in the first liquid.
 12. The liquid set according toclaim 7, wherein the second liquid includes a same polymerizable monomeras the polymerizable monomer included in the first liquid.
 13. Theliquid set according to claim 7, wherein the second liquid includes nocurable material.
 14. The liquid set according to claim 7, furthercomprising a third liquid having a third composition.
 15. A method ofmanufacturing a three-dimensional object comprising: imparting the firstliquid and the second liquid of the liquid set of claim 7 to form aliquid film; and curing the liquid film.
 16. A device for manufacturinga three-dimensional object comprising: an imparting device to impart thefirst liquid and the second liquid of the liquid set of claim 7 to forma liquid film; and a curing device to cure the liquid film.
 17. Thedevice according to claim 16, wherein the curing device includes anultraviolet light-emitting diode.
 18. The device according to claim 16,further comprising a smoothing device to smooth the liquid film cured.19. A gel object comprising: a solvent; and a polymer, wherein at leastone of 80 percent compressive stress-strain and modulus of elasticityhas a continuous gradient.
 20. The gel object according to claim 19,wherein 80 percent compressive stress-strain is 10-10,000 kPa.